"if carlsen goes to play big $$$ after a mere 10 weeks of instruction by ivey, he's gonna be broke really soon. nuff said."
This provides surprisingly little help in answering the question posed by the OP.
"also, when do non-poker players believe poker players when they say that winning "prestigious" tournaments is not what makes great players so great?"
Yeah, good poker players win tournaments more often... non poker players shouldn't be able to win at all! lol. In chess this is entirely nonexistent. There is occasionally a weaker player doing better than expected, but you have to know entirely what you're doing in chess for even this to happen. They don't just decide on a whim, hey I play chess once in a while, I think I'm going to go to a tournament with a bunch of GMs, and then maybe it'll be my lucky day. No, in chess, even a "weaker player" getting a good result is going to be a serious tournament player.
Even setting aside the random factor...Phil Ivey could teach Carlsen to play poker 90% as well as he does in about 8-10 weeks.
Just stop it...
Not 90%, but still, let's compare here. If Phil Ivey got lessons by Carlsen for 8-10 weeks, I mean, he wouldn't even be able to play .1% as well as Carlsen probably. I most certainly do not think that Carlsen's skill at poker would be nearly as imperceptible as that. In fact it probably isn't already.
Yeah, poker takes skill too, and I'm not a poker player, but there comes a point where giving the benefit of the doubt too much allows someone to post utter bullshit opinions with impunity. Chess isn't the one that has to explain total amateurs (literally!) winning "prestigious" tournaments.