But remember - the whole point of natural selection is that the system itself will evolve to find the best way of working only if we don't artificially interfere.
Of course this is the opposite of what control-freak politicians want to do, especially those who believe in massively centralised government.
The Achilles' heel of the command and control model is the quality of information flowing from the periphery to the centre. If this is not both accurate and comprehensive then decisions made centrally won't work - which is exactly where the NHS is at the moment. It is a very expensive and exceptionally inefficient system.
Take general practice. The centralised model suggests that GP practices need monitoring and controlling to force them to deliver what the NHS needs. That is why we have QOF targets, enhanced services and public surveys, all in place to try to tell the DoH who is good and who is bad. But because these measurements are superficial, scatter-gun and unrepresentative they don't do the job. They are also expensive to operate.
Now compare this with the Darwinian approach. Practices are already autonomous and in competition with each other. Provided they are left alone by government and given a level playing field, those that fulfil their patients' needs and expectations will attract more patients, survive and prosper. Those that do not will lose patients and, unless they change, ultimately fail.
This system is cheaper because it no longer requires hordes of administrators to monitor it. It is also more effective, because the judgments made by large numbers of patients are vastly more sensitive than any survey or set of statistics. Using this approach, practices are automatically encouraged to improve - at reduced cost.
Allowing practices to survive or fail through natural selection will create a cheaper, better primary care system. It is one way the NHS can save money while simultaneously raising standards. How sad that, although the principle of evolution has been known for 150 years, many politicians and managers have not learned its lessons.