Now the question is: how can we determine whether the new app update is better or worse? I think PMs and developers intend to produce better apps; but don't they realize that their updates are bad? That's why this issue needs more research to be understood IMO.
I think one of the indirect reasons is that in this world of countless options and emerging new things, people (including PMs and developers) don't want anymore to spend their years working on one thing and making / keeping it great. I'm sure there a lot more to it than this...
Very interesting discussion here.