As Good as it Gets

According to this BBC report, a study that will appear in the British Medical Journal says that a U.S. HMO provides better care than the British National Health Service, for approximately the same cost. The BBC report quotes one of the study's authors, Richard Feachem, as saying

If an NHS patient moved to Kaiser they would be delighted with the experience, and if a Kaiser patient moved to the NHS they would be horrified.

The report credits market competition as stimulating Kaiser to provide better care at comparable cost.

Discussion Question. Advocates of a "Patients' Bill of Rights" argue that legislation and the threat of lawsuits are needed in order to force HMO's to maintain quality. Why would markets and consumer choice not be sufficient?