> Why, if you're going to treat a founding or near-founding position as a 9-5, 40-hour week, clock-in-clock-out type of position, would you get a piece of the upside compared to just working at a bank or consulting firm?

One can be very dedicated on a 9-to-5 schedule. Just because you value WLB doesn't mean you are in a 'clock-in-clock-out' mentality. People have lives outside of work, may be even hobbies. The idea that a startup owns your life needs to die, stat. That is an extremely toxic line of thinking.