JT Aultz nearly died from a slam, from what I remember. I always assumed that’s what happened to him.
As for other names I can think of:
Jake Duncombe was huge, and I was convinced he was going to get SOTY around the time he Cab flipped the spine in KOTR (before shoe companies campaigned for SOTY). I know he piled out and his downfall was kinda his own fault, but man, he was incredible.
Sean Malto. If you stop and think about it, he never really had a ton of parts. He’s still around, but more of a “legacy” guy. He was billed as the “next Koston” but never met the expectations the industry and skaters thrust upon him.
Dennis Busenitz. Stay with me here - I know some people will think including his name here is slander. He’s probably my most influential skater ever. And he was incredibly productive for a long time. But he has been mostly absent for almost 10 years now. Yes his shoe is still in production, and he pops up with a clip here and there, but he hasn’t had a full part since Obama was president.