Except it's not upper management bleeding income, it's the company. They still get their golden parachutes and massive bonuses, then they downsize other parts of the company in order to claw back the costs. They don't have to worry about losing their healthcare or having to survive. Hell they don't even have to care about keeping the company alive, they can just straight up kill it and still reap the benefits like we've seen with Sears and the scumbag Eddie Lampert.
That's the risk. They destroy the bonuses and benefits of their workers to fuel their own rat race.
Employees also usually get bonuses, and stock options. Your point is possibly true for companies as big as FAANG ones, but for a startup invested in by YC, it's highly unlikely the founders are getting any real bonuses. They might get some money about in series B or C, but that's already less than 99.9% of startups that get to that stage probably.
You are simplying the situation by thinking about everyone as successful unicorns. Most companies and founders are not.
That's the risk. They destroy the bonuses and benefits of their workers to fuel their own rat race.