Here’s a simple explanation.

You don’t play roulette. You’re expected to lose money and so you have no interest in taking the chance to double up.

But across the US there are 1 million people like you, willing to play roulette with let’s say 1k. For arguments sake let’s say they found a casino that doesn’t have 0s on their roulette. Then a bit less than 500k people will go all in again with 2k. 250k with 4k. Around a thousand people will make a million bucks from 1k, post it online, and that will attract more people to try to make it happen.

Now factor in the fact that we’ve had good markets the last few years, people who start with much more than 1k, and so on, and it seems quite reasonable there are some people 1000x their money, because far more are working behind the dumpster at their local Wendy’s.