The problem is the anti-single payer faction in the US is large, powerful and well funded. They would do their level best to cripple any such system as badly as

The problem is the anti-single payer faction in the US is large, powerful and well funded. They would do their level best to cripple any such system as badly as possible, so they could say "I told you so", as they did with Obamacare. Therefore it is quite possible a single payer system in the US would not work out anywhere near as good a deal as it has almost everywhere else. It's hard to believe it could possibly still end up worse than the current system, but I worry that it would be a 'hold my beer' moment.