On Sat, 18 Nov 2006 20:31:53 GMT, "DDAY"
postulated :

What I'm trying to explore is why that is. Why was this technology really
popular for a couple of decades and then phased out? I don't think you can
say that better airfoil or wing technology replaced it. It's just that
requirements changed and the swing-wing was a solution that no longer fit
the existing problem set. But I'm willing to be proven wrong.

The swing wing was a maintenance nightmare.