The concept of an evil twin universe is so simple to understand, there's no doubt they could pull it off if they wished. And what's wrong with the universe they've already established? Seems fine to me.They can barely get their own universe down pat. What makes them think they can introduce a whole other one and hope to get it right?
I agree.
Also, when you think about the fact that the movies are primarily aimed at the general public, the mirror universe is one of the main, iconic tropes that people who know very little about Trek will recognize. That makes it a good box-office draw which, I think, makes it more likely that they will mine it for material.