I do know at least one person that day traded for a few years. He didn't get rich, but it was in the very nice salary range. Ultimately quit because it was stressful every morning starting all over.
This is also the same reason I only buy undervalued stocks that I hold for years. When I get to the age where I could retire I don't want to have to play the market every morning, I want to do other thing.
Why would playing the market result in higher returns? Why would you think day trading would outperform buying-and-holding? The research all shows the opposite.
I wasn't implying that playing the market would result in higher or lower returns simply that one person that I know that did day trade successfully did it as a full time gig.
This is also the same reason I only buy undervalued stocks that I hold for years. When I get to the age where I could retire I don't want to have to play the market every morning, I want to do other thing.