You were the one who wrote in a monetary figure, thus implying some monetary value to the “worth”. If you want to consider solely moral value, without any monetary component, then that obviously has different implications.

It's a matter of risk that I'm paying for to avoid, not absolute quality. I would not wager my life on a random doctor in Africa even while 90% of doctors there might be more skilled than in London. I'm paying to eliminate the risk of encountering the worst 10%. In that light, yes I would personally expect the doctors in London to be able to avoid the worst outcomes better on average. Whether that's warranted is another discussion.

This goes for loads of stuff. I would wager a $30 meal to be fresher than a $5 meal on average. I'm not saying there aren't any $5 meals that are fresher than some $30 meals, but just that the $30 has a lot lower chance to make me sick.

I think you're confusing a sometimes reasonable heuristic (you can get what you pay for), with some kind of underlying or real value.