How many mtts you have to play to win one?
Mtts are completely unsuitable to make a living form them. Especially live. Because you just can't have sufficient volume to overcome the variance. If we forget this "WAU cool. First place. I made 5 k from 5$" Then it boils down, to where do you have a bigger edge. MTT and cash games require completely different playing style. In Mtts you have more fish because of the possibility to win bigger money with very small buyin. But mtts are high variance game.
I read somewhere that best mtt players cash about 10 % of the time and finish in the first 3 places about 2 % of the time. From that you can calculate hourly, assuming that you are like best mtt players and considering stakes you play.
Then you can compare it to your hourly at the cash games. It follows optimistic for the mtt estimate, what you should play.