Evidence? There are certainly high performing single payer systems. The UK system is very popular, had good results and is economical.

The book The Healing of America by T.R. Reid compares the systems of Canada, the UK, France, Germany, and Japan. According to the book, the latter three get among the top results in the world, measured by international organizations on various objective criteria like survival rates after diagnosis of major disease. They have various costs, with Japan being especially low at 5% GDP. All three have competing nonprofit insurance companies, mandates, and price controls. At the time the book was written, they were performing significantly better than the UK and Canada (which were doing better than the U.S.).

The UK would be a weak hybrid "Beveridge Model" system, not single payer. The Scandinavian strong hybrid systems are even better. Just another instance of localism winning over centralisation.

https://en.wikipedia.org/wiki/Health_system#International_co...