That's not even an engineering salary, and you haven't factored in operational costs. It needs to be higher than this. And there's also no guarantee the business will last.
Plenty of people retire without engineering salaries in the US. $5k/month after taxes and expenses can be enough (or it can be a fraction of what you need).
Agree that thinking of it as a never ending money tap is the bigger issue.
But yeah if you gave me $10k/month pre-tax today (assuming it was never-ending) I’d be done working for the rest of my life.
The main issue with this narrative is that social security is on track to be insolvent in less than a decade. If that happens, then the long-tail of regular non-rich people are going to be in a world of hurt.