Self-Funded Success Traders: Why?

Self-Funded Success Traders: Why?
Photo by Shane / Unsplash
To me it seems that the only real reason to trade the foreign exchange is to get funded by a reputable company and use their money for bigger returns from small percentages. If you are self-funded, wouldn't it be better to just invest your money into the S&P500 instead?
The S&P500 has about a 10% yearly return. Most good traders don't even make that. And if you say you make more then i grow skeptical about you for every percentage higher than that. And add that onto the fact that the S&P500 is a lot more guaranteed than trading forex.
What keeps you in the forex market, considering that you don't care for prop firms. I'm not looking to be a know it all. I'm sure there is something I'm missing. Please educate me 🙂

The thing you're not accounting for is leverage, S&P isn't going to give you 50x (or more).

If I have $1,000 in S&P, sure I can make 10% [$100].

If I have $1,000 in FX with 50x leverage, now I make 10% of $50,000 [$5,000].