But there is a bound in both directions?

On end, it's "national insurance", functionally equivalent to fully-tax-funded healthcare like the NHS or the German system with several providers competing but regulated to near identical results, but moreso as the UK and Germany also has private care; on the other, it's the absence of insurance.

This is a macro problem larger than health insurance, and exists everywhere from employee bonuses, high school group project grades, handicap parking, gas prices, Everest summits, to gas prices.

Those might all seem wildly disconnected, but they all have systems of unfair allocation to compensate for unequal outcomes.

Generally national healthcare programs are entirely dependent on young healthy people paying into the system despite rarely needing it, and then hopefully enough dieing quick deaths or having multiple children to cover their costs. These rebalancing systems are artificial and humans are generally terrible at managing them.