Starbucks CEO Howard Schulz grew up in a Brooklyn Housing project, George Soros survived the holocaust and worked waiting tables, David Murdock of Dole Foods was homeless. There’s tons of examples.
Here’s a fun article that ranks the whole Fortune 400 list. 80% of them inherited their wealth or at least grew up middle class.
Jeff Bezos actually scores high on the list because his Mom had him when he was 17, he flipped burgers in high school and by and large did not grow up rich.