This is a strange hypothesis. I know of absolutely no one in my fairly large circle of acquaintances, friends, and family that seeks out, or highly desires, Tilapia. It is exactly the same as it was when you grew up -- a trash fish.
The only reason anyone willingly eats Tilapia is because, a) it is tasteless and they don't like fish, or b) it is dirt cheap.
And I find it fascinating that you think salmon is "out of favor" when it's on nearly every.single.menu of nearly every single respectable restaurant in the US.
Strange.