"...and nobody can tell you differently."

Yup. Pretty much. That's ego, though, not entrepreneurship.

A key piece of being an entrepreneur is faking it until you make it. It comes out in many forms:

1) Minimum viable product

2) Acting bigger than you are

3) Creating industries and markets that don't exist.

Without that ethos and world-view, which you call ego (it isn't), one would not survive as an entrepreneur.

"If you think you're an entrepreneur, most likely, you are one and nobody can tell you differently." ...which is exactly why people like it so much. It's an unassailable self-description. I think it's best to steer clear of anything that puts you in that position because its pretty easy to spin off the planet.