(yes, there are many, but it also depends on how are you defining rich. If you think of billionaires then it might be different.) I also say you need to adapt as you grow. So scalability is a topic for everyone who wants to grow a lot. That is why I am with currency trading. There is the most volume worldwide with distance. I also have different strategies from daytrading to longer term swing trading even to position trading. So when I have grown out of daytading once I can concentrate more on larger scale strategies.