I don't know a shooter under 30-years old that has one.
Here be one.
Here's another--not only under 30, but under half of 30. She's 14 in this pic, shooting her SP101 .357 Magnum.
However, the OP's point is well taken by me with regard to the .357. I'd not so much say it's "obsolete" but more "out of style." Its popularity on a forum such as this is not a reflection of its popularity with the public at large. It seems Joe Public generally wants an automatic chambered in .40 S&W or 9mm.
I think the .45 ACP remains as popular today as it was 5 yrs ago, even 10 yrs ago. When Joe Public opens a box in the ammo section and runs his fingers over a 230gr .45 cartridge, his eyes go wide and he smiles (like we all used to--heck, I still do!)
Anyway, it's a fun discussion. Somebody with the time, ought to track down sales data and see how many .357's are being sold out there.
Carry On!