I'd wager about 90% of any mass-produced form of media is crap, and anime is no exception. The isekai stuff is just a big part of the latest 90% for anime.

There can be hidden gems or interesting deconstructions of the genre, and sometimes crap can just be mindlessly entertaining.

I've started getting tired of the sheer amount of it, but I got tired of the 9 million mecha anime when I was younger, etc., as well.