@Ruin Explorer and
@el-remmen already covered in detail many of my feelings. I'll add that for me, personally, I can enjoy being a player in canon-heavy IP TTRPG. From my perspective as a player, it is no different than a GM who has a detailed world her or she created from scratch. Just let me know what I need to know about the setting and your campaign and expectations of tone at session zero and I'm good to go. Even if it is a setting I'm very familiar with, I don't mind what the GM does with it or whether the GM hews to continuity and canon. I accept the world as presented to me and focus on the party's story.
But running games in such setting--generally not for me. Pretty much for many of the same reasons other have posted about.
Then again, I have one exception. I love running games in The Old World setting of WFRP. Perhaps it helps that none of my players have any familiarity with the older versions of the game (either TTRPG or miniature war game) or the decades of fiction. While I hew fairly close to the setting material as presented in the 4th edition books and adventures, I also do not let myself feel constrained by them. There have been a number of times in the settings history where Games Workshop did major lore retcons, so it is matter of pick your version of the lore in many instances. I realize that all of this can be said about most or all major, long-lived settings.
So I guess it comes down to what setting do I most easily grok and naturally invest my time into, even outside of game prep, that an understanding of it has just seeped into me. Other than WFRP's The Old World, that has just always been my own homebrewed settings.
