I doubt all the engineers he has hired who have stock options have FU money. That would probably be a consideration.
We'd all hope so, but in practice it only depends on the board of Rubin's company and their goals.
In a startup company, everyone should be on the same page. A founder with FU money is not on the same page as an engineer risking 2-3 years for a shot at FU money. I'm almost certain that investors would look at an FU money founder differently than a ramen founder.
As a startup engineer, I have done this. There are startups. There are corporations. Both have their place and their appeal. But I'll avoid corporate startups.