I don’t know if you’re familiar with how bargaining works, but you only get the price break if you can come in as a large unified group. Having millions of individuals doesn’t result in a price break. Eg There are millions of private individuals buying health insurance in the US, but they have no bargaining power unless they purchase as a unified block. Individual health insurance policies are notoriously expensive.

Bargaining power can also come from the availability of competition. I don't collectively bargain to buy bread, but it's still competitively priced.

Good thing that police unions are notorious for being weak and ineffective, then!