If the pace isn't sustainable for a given person, that person probably shouldn't be trying to do a startup. This might seem a bit blunt, but I think it's probably true. There are many other options to bring the same financial and "impact" success that a startup provides and the expected value of these options is probably higher than creating a startup given an aversion to the high-intensity pace.
If 'startup' is defined by the pace, then you're correct. But do we all have the goal of making a successful startup, or of earning more money from your own idea? If the latter, there's an argument for a business model that allows a more humane pace. It may just not be compatible with many investors' models.
