Originally Posted by zachvac
I think it's possible to make a living at either one, I was under the impression that at least live most of the pros did tournaments. Online I guess cash games are possibly more profitable because of multi-tabling. Tough to do that with tourneys where there are a whole host of conditions that are constantly changing and players have to make reads based on this (how desperate are others getting?) along with individual changes they have to make (short-stacked, what's the prize structure, average stack, how many to the money, etc.). Cash game using something like Poker Tracker+PAHUD can get a lot of relevant stats that shouldn't change a ton because stack sizes and conditions are relatively constant.
Maybe Stars is different (though I'd be surprised), but I know it's always the case on Full Tilt - there's always quite a few $25-$50+ ring games going on, but most of the high stakes SnGs are empty.
Sure, people come out of the woodwork for things like the FTOPS or the Sunday Million tournaments, but it was my impression most of them worked cash games because that's where the more regular action is - same as live players.
I think you'll find the other reason they don't tend to play cash games live is because, unless they live in Vegas, they probably won't be able to find a game with high enough limits to be bothered with compared to the online games they can play.
The biggest live cash game players in the world tend to move to Vegas because that's where the action is. Online players may not want to do the same thing, so instead if they're going to play live they'll make a trip for a big live tournament, where they know there's going to be action (and likely some decent side games too).