As monetization becomes a bigger concern for a new app/service that was successful, I would tend to think that after a few cycles of getting better apps in general will get worse by increasing the amount of advertisements, requests for subscribing to something and dark pattern usage.

There's also the case of apps getting worse due to some company wanting to deprecate some feature in favor of another that is actually worse (some chat application that changed the way of doing video calls to take three clicks with loading times instead of one click ; some VPN app which changed the method of logging in so it takes one minute instead of one second)