Excellent point. There are plenty of ways to acquire the expertise you don't have (get a partner, hire someone, use an intern, etc.) to grow your business.

It's important to identify assumptions that limit your options or stop you cold. Thinking you can't do something is limiting; thinking "HOW can I solve this particular problem?" gets your mind to shift gears and instead generate solutions.

BTW, I love that Yoda quote--very apt.