Like any form of gambling, most games are chance, and the house has the edge. Very few people get rich fiat gambling, and this is no different with Ethereum. If you are skilled, Poker has the best odds of winning big, but even then, only a small percentage of very good players will do so.
Likewise, as an investment, Ethereum has and does make people nice returns but the average holder has not been made rich by it.
Treat it all like a bit of fun and never gamble on what you cannot afford to lose.