I give up. Disney can have Fox.

That's a valid point.  Otherwise, Logan was as much a standalone film as you're going to find featuring Marvel characters.  Even Deadpool relies heavily on your understanding of the events of the other films; hell, most of the humor consists of references to other comic book movies.  But all you really need to enjoy Logan is a basic understanding of the characters.  You could be a comic book fan and have never seen another X-Men movie in your life and still be blown away by how good Logan was.  

There are pros and cons to shared universes and stand alones.  What makes the MCU great are the endless possibilities.  You never know who might show up and how this story might connect to something else down the road.  It truly is a connected comic book universe on screen.  On the other hand, Nolan's Batman Trilogy was a separate entity and it (at least the first two, I didn't care for TDKR) was brilliant.  I'm sure filmmakers prefer a standalone because they can focus on the story they want to tell instead of worrying about how this will fit into the larger universe; but that's the price you pay with long form storytelling.  A television show can't just throw out the season before like it never happened (unless it's Dallas or Lost).     

The real issue is choosing which you prefer to make as a studio and sticking to it.  Marvel relies so heavily on continuity that it would be incredibly difficult for them to produce a one-off type film separate from the main universe.  Conversely, audiences will be asking how these films fit together when WB/DC starts putting out multiple Joker films and still trying to connect their central DCEU flicks, or when the X-Men timeline eventually catches up to Logan (which I suppose won't be an issue if the Disney deal goes through).  Like I said, I don't know if one is better than the other, they both have their advantages and their pitfalls.