Comment by Traubenfuchs

If you join early, got plenty of stock options and the startup turns into a unicorn, those millions are totally possible.

Until then, naturally, it's all paper money. A bet. Maybe an investment, of your time and effort.

The majority of startups fail and the majority of startups having an IPO will not make anyone rich via stock grants.

It's definitely a safer bet to find a high paying job in a stable company.