Gameplay innovation is risky. But if you spend a lot of money on looking good you don't want to risk that investment, so you just copy the gameplay of your last popular game, maybe with a new gameplay element from a competitors game
Fun has less to do with individual gameplay elements than execution. The balance between weapon types makes a huge difference in FPS games. Chip damage vs recovery mechanics, cover systems vs stealth vs run and gun etc.
Similarly there have been so many health systems in FPS games you don’t need to invent something particularly new, but you do need to pick something appropriate to the gameplay. For example in PvE players need to be able to fight waves of enemies but in PvP games nobody wants to stand for 30 seconds firing at a bullet sponge.
Puzzle games need interesting puzzles, racing games need appropriate tracks, and so forth.
We live in the golden age of gameplay innovation. It’s never been easier to develop and distribute a game. There is an vast ocean of indie game developers with new games coming out every week! There were 10394 new steam games listed in 2021. That’s over 28 new games per day! In 2010 only 349 games came out on the platform.
