You weren't specifying small businesses and even then I'd say you have to get super small, <20 employees for that effect to start making them equivalent.
I will concede that if every business was a small business, then unions likely would be unnecessary as the negotiating power is more equal
I didnt, i mean all business which includes small business.
Unions are a super-business organization, they affect both big and small business, and unions dont represent all workers.
If all workers were unionized, there would also be little point for unions.
There is concentration on both sides of that equation. Small businesses do not have the profits and margins big companies have.