A good work/life balance with a start up can be difficult, but not impossible. But unfortunately it happens in corporate life as well. I believe it is about priorities and setting a schedule to ensure they are met. Too many distractions (emails are a big one) get in the way.
As a company grows the entrepreneur should become an expert at leveraging. They should leverage Time, Relationships etc.
Having a personal growth plan is something I would recommend in order to achieve this balance.
I would enjoy chatting more about this.