[prostoalex]

Wouldn't those be compensated by inefficiencies introduced by the lack of negotiating power?

Prime example here is Medicare - it has an (albeit limited) ability to dictate the prices to participating providers due to its size. Remove the program, and everyone is left out to negotiate with their medical provider on a case-by-case basis, and we already know how well that worked out in practice (googlable via "runaway healthcare costs").