Well there's hardly any organisations funding FIFA teams (is that even a thing? Really not too familiar), but how are those players not doing anything for the real world? Ad revenue alone probably makes up for the money the teams give the players - streaming, merchandise, in-game stuffs.
If I used CSGO as an example, if you go from views from twitch.tv alone - the last Major Tournament (ESL One Katowice) peaked at about 850,000 concurrent viewers, and the total for the 3 days played was nearly 9 million. Those happen once every few months, with loads of smaller tournaments inbetween, all having a lot of viewers.
To go with that, as I said (and this goes for me too) - you dedicate your life to this; people play for as much time as possible, trying to perfect the smallest thing, leaving as little as possible to the RGN-like features of the game, even reaction time is getting perfected. It's hardly people who see each other once a year, playing for 5 minutes and raking in a grand...
