Ok, this is a horrendously stupid fucking question.
Perhaps most of my answer is supposition, you, thread creater, could use your brain to postulate similar things.
Park City: roughly 40-45 minutes from salt lake city. That means easy access to other big resorts and a major international airport. That's better than an obligatory 2+ hour drive to get to an airport (as in the case with whistler). If you're a travelin pro, that's nice.
Weather: Hood and whistler get PNW weather, which means gray and goopy but tons of fucking snow. Whistler usually gets a solid park, but hood... eh not so much. I think the big problem is that you're misconstruing the prominence of, say, Hood's (Timberline's) summer park with their winter park. While decent, it is not really world-class caliber, certainly not like that of many Colorado and PC parks, plus it's usually gray all the fucking time.
Money: You realize how many incentives Pep and Tanner got to go to Park City from Mammoth? Then again, they're never there. It's just a form of advertisement for PC.
Seasons: This can be attributed to weather. Most of the people you mentioned end up in places like whistler, hood, NZ, europe during the summer when a place like utah is unskiable.
school: Major ski bum university in very close proximity. Funny how that attracts young skiers.
questions: stop asking dumb ones.