Businesses can’t get together and fix prices, but union members can use their right of free association to fix the price of their labor. And if the employer doesn’t agree, then they strike and the employer can NOT fire strikers. If he replaces the striking workers, the union members commit violent acts against the replacements (scabs to unions) and refuse the allow the employer to carry on his lawful business. This is not free association and bargaining, it is extortion and would be illegal in any other context.
You are missing what I am saying. I know unions suck now. I am saying though, that the answer is Freedom. Let them get together and form a union, and let the employer fire them if they want. If the union commits crimes, then those are crimes.