The government already does decide which drugs to fund, just at a different stage of the pipeline. Also, it honestly probably will be about as efficient, since

The government already does decide which drugs to fund, just at a different stage of the pipeline. Also, it honestly probably will be about as efficient, since we subsidize a lot of medicine’s private R&D already (eg orphan drugs), not to mention eliminating the rentiership of private IP and (some of) the waste of pharmaceutical marketing