aca di. implement a market, it's just that most people buy through their job, because if that's legal you obviously want to be part of a larger bargaining pool for buying.
It isn’t really bargaining power of the pool, but the risk assessment of the pool you are in. Being in a hodge lodge personal pool means you are sharing risk with people who will have more expenses. That’s why Switzerland throws everyone into the same pool, so no crème low risk can be siphoned away.