In 1962, Wilt Chamberlain scores an NBA-record 100 points

This is the point, you had to earn it.  Everyone plays matador defense today because everything is a foul.  Replay after replay after replay to see if a guy followed through too much on a blocked shot, so it can be determined a flagrant 1 or 2.  It's impossible to say the defensive intensity was exaggerated when the video evidence proves otherwise.  It was a much more physical league back then.  Looking at scoring averages alone doesn't explain the differences in style of play.  Go back and actually watch the games instead of basing your opinion on numbers you found.  Watch the games.  The leagues in the late 80s-90s was much more physical than it is today, and points were earned, as your free throws anecdote points out.  Like I said earlier, the term 'playoff foul' didn't come from nowhere.  You aren't allowed to do that stuff anymore.  The physicality of past eras made the game harder and shortened careers, this is indisputable.

The physical defense didn't affect the scoring average because those players grew up with that style of play.  Put an 80s-90s superstar in todays league and they wouldn't believe how easy it is to score.  Put today's superstars in the late 80s-90s (post McHale clothesline, prime Bad Boys and Ewing Knicks era, so stop using a lone game from 1983 as the quintessential '80s-90s era' NBA) and they'd start crying after their first hard foul.  I'm not mellowmoviereview so you don't need to defend LeBron to me.  LeBron predates the soft league we have on our hands now.  I take more issue with the pure shooters that don't do much else, like Curry and Klay, or flop artists like Harden.  These guys wouldn't have thrived in those days (again 'those days' being the latter half of the 80s and the entire decade of the 90s), they would've been serviceable at best.  Harden I could see being a quality player, but Klay and Steph would've been role players.  Never mind hard fouls, some good ol' hand checking would've made their life miserable.  

Learn more about those eras.  Read about the style of play, not just statistics.  Jim Loscutoff had his number retired by the Celtics and he averaged 6 points a game for his career.  His nickname was 'Jungle Jim' because he was built like a beast and his job was to come into the game and throw people around if they got out of line.  That role doesn't exist in today's NBA.  See?  Even when the league was putting up tons of points in an up tempo style of play, the game was still rough in a way it just isn't today.  

The athletes today are as talented as they've ever been in this league, that isn't a question.  I don't love the three point crazy format (which is highly ironic if you had grown up playing basketball with me), but today's NBA requires a level of skill from more of its players overall than it did in the past.  They aren't a bunch of bums out there.  But there is an enormous difference in physicality from the old days to today, and that should be taken into consideration when comparing legacies and the overall impact on a player's accomplishments.