Nobody cares if what you built is sustainable and scalable if you can't do it fast enough to get your first customers, and there is plenty of time to make what you've built usable by the time you've left.

If you, as a founder, hire an incompetent specialist as your first employee, maybe you don't deserve to be successful.

Your first hire is either a "Brent", or you have to get very lucky in just about every way.