True, as a gambler, it will be difficult for you to win your money, it will be worse if you do this full time and you will only rely on that as your source of income. Knowing that gambling comes with risk, and gambling is difficult because you cannot predict it. Those who don't know how to balance and analyze the statistics and manage their finances wisely, therefore they will not make a successful career in terms of gambling.
On the other side, yes we can make gambling a successful career if we apply our knowledge and skills of the expertise that we have. For instance, working as a game developer by creating online casino games, slots, poker etc. Or maybe apply as an affiliate marketer like promoting gambling websites and casinos online, or you can be a casino manager. See, there are chances that some people can make a successful career in gambling but just make sure that the company or management that you are applying for has been functioning for a long time and check if they are successful through the years, for you to have a job in the long run.
gambling is very difficult to predict, even professional gamblers are not spared from losing, if you have just enough money and want to start a gambling career, especially in gambling that uses skill, you should abandon your intention because you will experience losses, is better to use the money for other business capital which is more certain to be profitable than gambling which provides profits not sure.My point is that, if you apply your skills in the game that you are an expert of and learn its tactics and its flow then you rarely lose and only lose a little. If you don't know how to play the game, then of course you will lose more. In gambling, you should not rely on luck but also use your brain as well. It is also crucial that you should really know how to manage your bankroll instead of spending your money aimlessly.
Anyways, you are right that it is better to use the money for business, but the problem is if you are not good at handling business then this will be going to lead you into bankruptcy. You should still study it so you can gain more ideas about what your business should be.