Not only is luck a big part of the play but even if somebody is able to pull this off and make a living off gambling, it would not work infinitely.
This depends on the kind of game a gambler is playing. When we say a gambler can make a living, that already implies consistency.
For example, if someone is making a living through sports betting, I don’t think that will just stop in the future. The leagues will continue, and as long as the gambler stays updated and their method keeps working, it won’t become obsolete.