I suspect that mostly the guys who relied more on their own character rather than an assigned gimmick would be most likely to still work (get over) today.
Guys like Bill Eadie, Jake, Bret, Austin, etc. would fare much better than guys like Adam Bomb, Duke the Dumpster, and the Ultimate Asshole.
Some guys like Adrian, Eadie & Scott Hall were given gimmicks, but strongly incorporated their own style and personality. To me, those are the guys who could withstand the test of time. Their style was timeless, and they could no dobut adapt to what evolution called for.
I wish some of those guys would have stayed on longer for that reason. It would have been great to have Adrian, Eadie, and Jake around longer. Adrian died in an automobile accident. Bill suffered a heart scare that more or less forced him into early retirement from the mainstream. And, Jake still had good momentum towards the end of his last high-profile WWF run, but was put out to pasture because of his substance problems.
One more note worth mentioning is that Demolition Ax was supposedly in line for some kind of road agent or booker position. In fact, management allegedly told him that he would assume that role following the disbanding of Demo. They stalled, keeping Bill in the dark for several months. I don't know if he ever did get anykind of formal decision from them, but it's a shame to have wasted a talent like The Masked Superstar.