Gambling for sure is a tax on those unable to do maths.
That said there was (maybe still is , I'm not sure) a very profitable period where many people made very good full time livings from online poker. Poker is slightly different from other games in that , although the house always takes their cut (rake) , if you are significantly better than the other players (plus rake) you can win long term.
From about 2006-2010 was the golden era, even a basic understanding of strategy could earn a living. After that the sites got a bit wiser, raised rakes, implemented strategies to minimize the edge of the sharks. The shark pool increased and their strategies evolved.
I played as a hobby, enjoying the math and strategy, wrote a few bits of software for calculations. It was profitable but became a bore, and less profitable so I haven't played in years. I recall in 2011 on a strategy discussion skype group, a 20 year old dutch guy wondering where to put his years winnings of EUR 100k (typical of decent players at the time) ..... and a Canadian frantically trying to tell him not to invest it in bitcoin. Good times.