Maybe some people don't find sitting in meetings all day to be all that satisifying. But they are stuck in it due to family expenses. Maybe they would prefer something more stimulating, if they could have the chance.
The default state of the startup should be: _fun_.
More fun than you would have by being required to show up and remain for eight or more hours each day at a corporate campus where you can clearly see people are not getting much done, but are relying on their position as a source of corporate-sponsored welfare.
To work on a startup should be a privilege for anyone who has worked in a corporate setting for any length of time.
Riding on the success of a large corporation is easy. In many cases all you need to do is show up. But that doesn't always mean you were "a success" or a part of the reason for the company's success. You may have come along after they had already succeeded, looking for an easy payout. Some people make a career out of this. They never join early stage companies. Again, there are family expenses and these motivate people's decisions.
Working on a startup is a way to be able to take full credit for whatever happens. It might be credit for failure. It might be for success. But at least you know you were responsible, and not riding on someone else's coattails.