Fractional-reserve banking. Most people have no idea what it is, probably a good thing. You could argue that it’s not a “secret”, but most people aren’t aware of it regardless. I don’t think most people would be fond of grinding for $15 an hour if they knew banks could just lend money they don’t actually have. https://en.wikipedia.org/wiki/Fractional-reserve_banking
Uber effectively weaseled their way into the taxi industry by somehow enticing drivers to work for them while also assuming all of the liabilities. Truly, capitalism at its finest.