The industry is mature and trying to squeeze out every cent it can from as many customers as possible now.

Boring flat UIs are more amenable to being endlessly tweaked and AB tested by product managers with no vision other than “make metric go up”. UIs are thoroughly tested to ensure people will engage with the product as long as possible, in the ways that are most beneficial to the product owners.

It’s the difference between hanging out in your friend’s backyard, and hanging out in Disneyland.

As a user, it sucks. Only way out is to actively pursue and use software made by small, human developers rather megacorps. There is still fun, quirky software out there but it doesn’t have $100M marketing budgets so it’s on you to find it.