The way I read you comment is that "the company can just spend more" so that everyone can work 9-5. The reality of starting a business, or even running a business in general, is that cash is limited (isn't it always?).
It's not about 'working for free', either. It's recognising what the reality is. Working for a startup is a choice and a trade-off. IMHO, wanting to work for a startup but only 9-5 is a little unrealistic.
What you describe is a little bit working for free. If you’re not being paid for those hours and you do not have a stake in the business, then you are effectively giving money to the owner.
It's not about 'working for free', either. It's recognising what the reality is. Working for a startup is a choice and a trade-off. IMHO, wanting to work for a startup but only 9-5 is a little unrealistic.