If you are day trader you can make decent income, you can actually earn quite a lot but the fact is there is practically 0% chance that you will end up in top 100 forbes list if you are just doing day trading
What kind of investing/trading do you have to do to become SUPER rich, like earn BILLIONS$? What should be your approach in theory?
To do it oneself, I don't think it is possible to make even one billion starting with small sum. Yes yes yes, an experienced trader can run up a small account to larger, and to be honest the hardest part is actually taking a 5k account and getting to 100k, but at some point you have to cut back risk. Starting out, often time one might be using $2500 to have in an account to trade one ES till you quad your funds, but at some point you have to increase the $2500 to reasonable about 5-10k, there are so many possibilities of ruin in this game you might be unaware and because of lack of experience, younger trader is walking into quicksand. You pretty much have to open up a firm of either your money you have slaved to build up and have others trade your fund while monitoring them or start a hedge fund and charge much more than most.
Doing it oneself, long term stocks and commodities, but that is not nearly enough, have to be making options plays constantly around the longer term trading, and to do it manually, I think impossible. Day trading has to be automated, so much harder now with watered down ES at $50 a point when it use to be $500 a point, there are too many products to trade while reduces volume on individual instruments, and this causes spreads to be wider and stops to be run with more slippage.
As far as "How much is enough"? Some happy to have $500k and others keep playing to make billions, once your house is paid off, have enough funds to cover you till age 100, anything else to donate to charities. And why not keep trading and racking it up, took you years to get good at it.
But I think at some point, making beyond certain amount would add many problems to one's life than add. Who do you trust? People run to you in hopes of your knowledge rubbing off, you have to have body guards, putting large electric fences to keep people out and for what? If not for ego trip, I would imagine it very lonely at the top.