Part of it is the massive expansion to include more people by making the games and mechanics as basic as possible, but the major driver is the rise of streaming and multiplayer becoming the default and most important mode for games, if not the only option.

Strong single-player storytelling and action has been sidelined, and most multiplayer games tend to be the same. Some have unique mechanics and gameplay but they all depend on your team and unless you have a very good group of people to play with, it just ends up feeling bland and repetitive.