Of course there are strategies. You even have to develop them based on the cards you get and your position in the game. Poker without strategy would not be poker. Before you start playing poker, you should first consider some simple strategies. These include good money management, otherwise you will quickly become a poor man.
Meaning you can be successful playing poker with good money management and strategy? Do you know anyone anywhere that earns consistently from poker by depending on strategy, good money management, skills, etc?
If such people exist, then I don't see much difference between them and those earning sustainably from their businesses. People should aquire the right skills before going into poker, I think.
Poker is all about having good skill sand strategy to beat opponents. If someone is really good at it and can earn very good amount form it then yes they do not have to do job or businesses because playing poker and making money itself become job for them and there would be people who are depended upon the gambling money from the winnings by playing poker and other games.