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.
This makes sense if the case is probably like this, people will be rich and alive from gambling.
however, it is probably only some percentage of the gamblers having this chance and conditions.
Even a professional player will not always win, they will probably lose in a day. But he tries again and make back their money from losing by winning other gamblings. probably but, how much is the percentage to take back the winning? As we are not that professional gamblers, we may not know, but for them, they probably really know how to make it.
Losing and winning in gambling maybe like what we are experiencing in trading. But with different strategies and tactics.