Studies consistently show that reading for entertainment is in decline worldwide. With this in mind, is it still worth it to try writing fiction as a career?

It is never worth trying to write fiction as a career.

97.5% of all fiction writers do not make a living at it, and of those that do, most of them make just enough to get by. It is a known fact that writers make less than minimum wage.

That has always been the case. The difference between 60 years ago and now is that it was possible to make a living writing other things than fiction. Between non-fiction articles in magazines, newspaper stories, pulp fiction and porn, it was possible to make a decent living. That is no longer the case.