I have another answer: It’s because true innovation is hard.
We have a ton of super-popular violent games to source ideas from for new games. We take an idea and modify it a little, and it’s fun.
We don’t have nearly as many super-popular non-violent games to source from. They exist, but there just aren’t as many of them, and they’re generally pretty “cozy” instead of pumping the adrenaline. Sports/racing games are an exception, but “non-violent” still depends on the exact sport and implementation. Many of them aren’t non-violent.
It’s the same reason that fantasy often still uses elves, trolls, and dwarves. They’re really easy to source from, and coming up with compelling new races that aren’t essentially the same as the tropes is hard.
Indies are into innovation. AAAs are into money.
Gee, I think that’s about the same time they decided that they community wanted more difficulty and made the decision to make the lowest levels of the game into bullet-sponges and to make no changes at all to the parts of the game that veteran players wanted more difficulty in.
Now it’s super grindy for veterans, and not fun for newbies. Exactly the opposite of what was wanted by all.
I am not at all surprised that people are quitting.