When prices, availability and standards are all fixed centrally, they give no indication of whether the system is working properly, so those in charge have to set up intrusive and expensive investigations to find out.
This is why centrally directed projects can't work sensitively without targets and surveys - and even then everyone wonders whether these surveys are statistically accurate, whether they have asked the right questions or are truly representative.
All this is redundant in a free market. Not only does it react automatically to surpluses and shortages but the market itself provides subtle and detailed information about the quality, convenience and cost-effectiveness of its goods and services - and all for zero outlay, because it requires no surveys, no statistical interpretation and no management or user input.
If only the NHS were run as a truly free market, think what we would gain. Gone would be the government's need to assess healthcare via simplistic targets like access times, length of consultation, opening hours, and the possession of written protocols.
A truly free market in primary care would have no rules over where new practices can site themselves, or how they should be configured; it would remove all professional restrictions on advertising and promote nationally the idea that patients can change doctors without moving house.
Patients would vote with their feet, trading off speed of access against the need to wait to see the excellent Dr X; the availability (or irrelevance) of extended opening; or the extent, quality and convenience of practice facilities and infrastructure. The patients themselves will perform the equivalent of the government's assessment calculations - and more subtly.
List sizes will soon indicate which practices are fulfilling patients' true requirements. Practices will be able to spend more time caring for the sick rather than having to prove themselves by ticking boxes.
And all at no expense. No wonder NHS managers don't want true free-market primary care - they would be out of a job.
Dr Lancelot is a GP from Lancashire. Email him at GPcolumnists@haymarket.com.