None of that is relevant to the employer-employee relationship. My employer's competition is not my competition. Even if there were no hiring competitors, they would still not be my competition. I would still want equitable bargaining power with my employer.

And regardless of that, if my employer is willing to pay our CEO over 20x what they pay their average employee, they are not in a position to niggle over the kinds of systemic inefficiencies they would suffer under a union.