While these dinosaurs may not roam anymore and may spend most of their days in safes, I don't think interest in them is extinct at all. While I don't consider 10mm to be remotely in the 'magnum' class, still, it's a member of the 'significantly more powerful than average' auto pistol club--and there's considerable interest. Agreed, that interest is tiny compared to the interest of the masses in the next 9x19, but that interest is intense and persistent.
Glock just began producing its 3rd 10mm auto--a longslide--and while it is even more hideous than anything it has produced to date, I doubt they built it just because they could. The caliber has a very loyal, if limited, following.
Now, my impression is that many (if not most) 10mm shooters seem to believe the round is capable of taking out enemy armor if only it is loaded far enough beyond max book. It seems many handloaders desperately want the cartridge to live up to its legend and produce more than the little feller is up to. I take this to mean more is better, which AFAIK, has always been the case.
For many, myself included, there's no desire to shoot 500 SW Magnum and no desire to shoot revolvers. There's a strong desire for an
automatic in a respectably powerful caliber--and 10mm isn't it. I happen to think 10mm is just about 'the best' auto pistol cartridge we have available, all around (punch, capacity etc), but it's a stretch to compare it to 357, 41 or 44 IMO--at least if you ever want to reload the spent brass again.
Folks will certainly always ask 'why' and in one way that question is a good one to ask. But 'more powerful' and 'more compact' have been the marching orders for the entire history of personal weapons, I think--it sure isn't going to stop with the revolver. At some point though, one has to 'call it' and make the transition from handheld to shoulder-fired, with mass being the only thing that can stall that transition. In a world where the short-barrel rifle had more room to develop, this transition would be a smooth one in terms of technology and personal choice. Right now, the government gets in the way I think.
I'm doing my part to keep the dinosaurs roaming--the overweight, oversized and overpowered impractical novelty is in the mail!!!