There are many people who indulge in gambling activities but I don’t think they gamble as their major source of income. They gamble to add up to their financial status, they play gamble as a side hustle. But in a case whereby the gambling is favoring the person, you don’t expect the person to quit gambling.
This is what many individual on this thread failed to understand, that those who made some income or a living from this industry were those who don't gamble or chase their losses. Most professionals we saw on the list have other sources of income and not just rely on gambling alone. Some of us here gamble as a side hustle, particularly myself.
Well, this might be for some, which also have some side-businesses related to gambling, e.g. referring new members or being incluencers for gambling businesses. But there is also a minority which can solely live from income that completely results from doing gambling, mostly betting. I would say it is less than 1% of all gamblers, but they have managed to come up with a strategy / a way that will make them profitable in the long run.
definitely, these people have learned certain tactics to be able to win even not every day, but I'm sure monthly they have profit, and yes since gambling online has some referral incentives, maybe they also get from that as well, playing for a long time means they know some patterns that they are sure what will be the result, that's why they spent a lot of times gambling because if not they are already broke right now and won't play or gamble.