Some are casters, like T90[0]. They stream a couple of hours of AoE2 commentary every day on Twitch. They collect income from Twitch subscriptions and donations and also Youtube ad revenue. It's very hard work for not a lot of money.
A very small handful of top players plays it full time. Viper[1] is the "top guy" currently and he streams on Twitch. So his income is Twitch + Youtube + tournament winnings.
There are about ~5 people that do AoE2 full-time. The #1 player in the world, TheViper, has over 1000 subscribers on Twitch (~$4 / mo each after twitch fees). So that's $50k/year just in Twitch subscribers. He probably averages another $25k/year in tournament winnings, and at least that in donations, probably a lot more. So at least ~$100k / yr.
T90Official (USA) and MembTV (Spain) are both full-time casters of pro & semi-pro matches, and they probably make $75k and $50k respectively per year, based on their sub counts and what I know of their donations.
