I feel like most businesses would probably prefer to pay workers more because of collective bargaining and worry less about compliance, but a variety of legal and social changes keep collective bargaining from happening. Unions in California were criticized in a recent forbes opinion piece I read for wanting to exempt union run shops from the minimum wage, but frankly, that seems like a sensible position to take.
Unfortunately most advocates of the free market seem to hate unions, so any advantage collective bargaining might have over government regulation in terms of giving employees a fair deal while keeping regulatory costs low gets downplayed.
edit: I put a space between any and advantage to fix a typo.