Well, it certainly says that the general population isn't terribly interested in hearing about CATS. I think that CATS is the successful show that is most hated - whether people know why they hate it or not. A musical about people dressed up as cats is all it takes for most of America to already cringe and laugh.
So why you have a point that no, audiences (TV) aren't interesed in CATS, I don't think that says anything about musical theatre as an art form. And certainly, theatre is generally incredibly relevant - but it can only be as relevant as you let it be.
"If you are going to do something, do it well. And leave something witchy."
-Charlie Manson