Why did FSW never catch on?

I’ve been a member here a few months – part of a renewed interest in aerospace I last had when I was a kid.

Back then (early ’80s) it looked as though a lot of future high performance aircraft were going to be forward-swept – certainly many of the preliminary designs had that configuration. At the time, the X-29 had just appeared and was gathering good reviews, for example.

What happened? I don’t think there’s a single example of a military FSW aircraft in production; correct me if I’m wrong. What would the reasons be for the failure of the concept?