Honestly, I would say CoD. If I still had internet I'd be grinding out wager matches/events. It's the best $$ if you put the time in.
From being seeded 15th in the pro bracket throughout the Blops 1/Black ops 2 seasons we made decent money. (Event seedings, not gamebattles seedings. We were 3rd and 9th on the GB ladders)
Crazy how much you can make streaming if you get 4 people together and grind out a game for a few months.
LoL if you can get to challenger tier you can sell the accounts for a lot and teams will try to pick you up for events randomly.
I'd say now in the CoD world it's around $100k a year for a lower top tier player, I know most of the older guys and they'd agree with that.
LoL can range GREATLY, if your a top 8 team your going to make a million + a year with all of the free tech stuff you'd ever want.
Or lower tier making money from streaming probably around $30k-40k a year if you keep a high viewer rate.
Pre-CoD I was into CS 1.6 and it was ok money, not great. Couldn't tell you about today all I do is comp solo.