That's kind of the point: it's absurd to expect an employee--who doesn't see either the same rewards or the same risks as founders--to be as passionate about the company as the founders are. I'd go further--it's not just absurd, but astoundingly stupid and naive. It demonstrates a profound lack of both reasoning ability and experience.

Nothing stops a founder from walking away. Plenty of founders sell their shares to investors/cofounders in order to cash out.

Boards are typically stacked in the founders favor, so any reduction in pay would be the founders own decision. Which makes sense, because they want to keep the company that they have significant equity in alive.