In addition to what AG said, I would like to point out in the mid 1990s HMOs tried to say no to certain procedures (mostly because of high cost/low expected benefit) but the people hated that idea that the HMO said no, so they forced the government to force the HMOs to say "yes" essentially (which is the reason for the higher cost to GDP). Given the fact that the U.S. is a democracy, and people get upset with even talking about changing social security or Medicare, it seems unlikely the public would tolerate the gov't denying certain procedures (even ones with low expected benefits) (if the politician supported such a measure, he'd prob. be voted out).
The section on "for profit" and "not for profit" hospitals is somewhat deceptive. For profit hospitals, like the name implies gives returns to investors, "not for profit" hospital's profits go to the doctors at the hospital. Since the doctors actually receive more money at "not for profit" hospitals, they have direct incentives to lower costs and work more efficiently. If the government was in charge of hospitals, I think the "not for profit" positive effects we currently see would disappear (since profits would go to the government, not the doctors). "For profit" hospitals also have a benefit compared to "not for profit" ones, but I don't remember it or the source off hand (I'll post it if I find it).