Not in the slightest (in short... re-watching keeps me interested in movies)...
while there are at least tens of thousands of movies, if not hundreds of thousands or so, it's safe to say a VERY high percentage are nothing special, so I would not worry about it. because I am confident had I seen double or triple or quadruple etc the volume of total movies I have seen up to this point (call it up through 2019), which is 2,275+ total movies, the volume of movies I consider favorite movies would not be much over where it's at now (i.e. 154 movies, 187 if I count movies a bit shy of favorite movie status). hell, even trying to account for roughly a wider range of peoples tastes (as in listing movies at least a fair amount of people think stand out) I can't imagine there are more than maybe 1000-2000 movies or so that stand out AT THE MOST off the top of my head. so if I am in the ball park on that estimate... that just shows you a lot of movies are pretty much average-ish at best and are largely forgettable. hence, Thumbs Down. because my basic goal of watching movies is to find ones I want to re-watch from time and, preferably ones that stand out from the pack.
personally I would lose most of my interest in movies if I rarely or never re-watched movies simply because I feel have largely exhausted seeing the movies of the past that would be of any real worth for me as while some quality movies still turn up here and there for me into the future, it's getting much more difficult to find movies that I have not already seen that stand out for me in the past and it's been like this for years now and I have seen 2,275+ total movies. because I don't see all that much point of seeing say double or triple or more the volume of movies I have already seen because I doubt my favorite movies would change all that much had I seen a much higher volume of movies from 2019 and older.
or another way to see it... when I re-watch a movie I am much more likely to get a solid level of entertainment from it vs watching a random movie I have not seen before which there is a good chance it will be forgettable (or at the very least, nothing special) simply because when looking at the facts for me only about 20% TOPS of everything I have seen is worth re-watching and only around 7-8% of everything I have seen that stand out from the pack for me to call a favorite movie. with that said, do I think there are some undiscovered gems I have not seen in the past? ; yes, but... ill likely have to watch a bunch of largely forgettable movies to 'maybe' find a decent gem once in a while which is why I am in no rush to see plenty of additional movies from the past at this point in time as ill just watch whatever I watch and whatever happens, happens.
just looking at 2012 to date on a yearly basis here are some facts for me in terms of first viewings vs re-watches of ALL movies I have seen (which means regardless of release year of the movie)...
2012...
-Total Movies = 239 movies
-First Viewings = 119 movies (49.8%)
-Re-watches = 120 movies (50.2%)
-Yearly Average (movies per week) = 4.57
-Yearly Average (movies per month) = 19.92
2013
-Total Movies = 233 movies
-First Viewings = 107 movies (45.9%)
-Re-watches = 126 movies (54.1%)
-Yearly Average (movies per week) = 4.47
-Yearly Average (movies per month) = 19.42
2014...
-Total Movies = 336 movies
-First Viewings = 145 movies (43.2%)
-Re-watches = 191 movies (56.8%)
-Yearly Average (movies per week) = 6.44
-Yearly Average (movies per month) = 28.00
2015...
-Total Movies = 301 movies
-First Viewings = 105 movies (34.9%)
-Re-watches = 196 movies (65.1%)
-Yearly Average (movies per week) = 5.77
-Yearly Average (movies per month) = 25.08
2016...
-Total Movies = 274 movies
-First Viewings = 89 movies (32.5%)
-Re-watches = 185 movies (67.5%)
-Yearly Average (movies per week) = 5.24
-Yearly Average (movies per month) = 22.83
2017...
-Total Movies = 223 movies
-First Viewings = 140 movies (62.8%)
-Re-watches = 83 movies (37.2%)
-Yearly Average (movies per week) = 4.28
-Yearly Average (movies per month) = 18.58
2018...
-Total Movies = 154 movies
-First Viewings = 57 movies (37.0%)
-Re-watches = 97 movies (63.0%)
-Yearly Average (movies per week) = 2.95
-Yearly Average (movies per month) = 12.83
2019...
-Total Movies = 278 movies
-First Viewings = 48 movies (17.3%)
-Re-watches = 230 movies (82.7%)
-Yearly Average (movies per week) = 5.33
-Yearly Average (movies per month) = 23.17
so as you can see... 2019 is hands down the biggest gap so far in terms of percentage of first viewings vs re-watches and that 2012 was the only year very close for the 'first viewings' overtaking 're-watches' in terms of volume of movies seen in the given year.
I don't think it's so much that out taste in movies is limited etc, but more so that a high percentage of movies are nothing special straight up.
in my mind, it's just a fact that the vast majority of movies are nothing special and I can't see anyone disagreeing with this otherwise they are that type who's too easily pleased. because once you have seen plenty of movies, you can start to really see what stands out from the pack vs just-another-movie sort of thing. because for someone who's not seen many movies I suspect they will be more easily pleased vs someone who's seen plenty. plus, some types of movies just ain't that interesting even though what genres are interesting and what's not varies from person to person.
and after a while you can generally tell what you like and what you likely won't. either way, a person will have to be selective on what they watch simply because it's pretty much impossible to watch everything as we only have so much time. so people tend to be more selective because of it and stick to what they are more likely to like etc. because I figure once someone goes too far off the radar, your going to be watching mostly average AT BEST level of movies. I would not even want to watch even remotely close to all movies because I can say with certainty many would flat out waste my time (especially when you start seeing many thousands or more as while I gave about 80% of everything a I have seen a Thumbs Down, I will say that most of what I have seen did not waste my time. but had I seen roughly double or triple the volume of what I have currently seen I suspect a lot more would be mostly wasting my time) to where I would rather re-watch a movie I know I like and will likely deliver a solid level of entertainment etc.
another thing... as a general guideline, anything I score a 7/10 or higher (probably even 6-6.5/10's to) ill re-watch at least once every few years or so. I try not to re-watch something too often though as after I have seen a movie twice, I won't re-watch it more often than once a year at the soonest and typically no longer than 3-ish years. but for movies I give a 6/10 (i.e. a mild Thumbs Up)... these might not be seen for 5-ish years, possibly more, but some could be sooner say once every 2-3 years or so (but I am mainly concerned with the stuff that stands out tends to see the most re-watches as a general guideline). but every now and then ill go through movies I score a 6/10 and do a little clean-up one could say as if I have no desire to re-watch something within a fairly reasonable time frame, I might switch it's score back to a 5/10(Thumbs Down).
p.s. I never restrict ratings on movies but it's just that only a small amount of movies interest/entertain me to a higher degree and my ratings reflect this fact. because the more interesting/entertaining a movie is to watch, the higher the score. the further it gets away from that the lower the rating. my basic baseline scoring system works like this... 5/10 or less = Thumbs Down(won't re-watch(with rare exception)). 6/10 or higher = Thumbs Up(worth re-watching). although 7's and higher start 'favorite movie' status and I use 6-6.5/10 for movies a bit shy of that status with 6/10's being a mild thumbs up. 5/10's are average but since average is not worth re-watching, it's ultimately a Thumbs Down. then I got 4/10 as below average, with a 3/10 being pretty bad, with a 2/10 being reserved for boring (which is pretty much the worst crime a movie can commit), and my 1/10's for movies that I greatly dislike which is fairly rare I find these movies which is why I tend to use 2/10 as my typical bottom-of-the-barrel score. most movies I see score a 5/10 with a 6/10 being the next most common etc.