The whole society pays for everything that is shared. Like roads. Or White House. Expensive cars and plane tickets subsidize cheap ones.

The reason costs go up is because in some countries someone sees health insurance more as an opportunity to line their pockets since there is less transparency on how the money is spent and the pool is so big it offers temptation. But this is a problem of implementation, not the system’s concept. This is corruption where “negotiations” with healthcare providers and pharma are more about commissions and bribes so the actual costs don’t matter.

Same as with the road building I mentioned above. Is rod building soacialist?