Because there simply isn't that much variation in prices elsewhere. In fact, in many countries there will be exactly one price for any given treatment.
For example, in Switzerland, each treatment etc. is assigned a specific number of fee points (Taxpunkte). This is multiplied by a conversion factor to arrive at the cost of the treatment that a doctor can bill your insurance. And that's that. Unless the treatment allows for variations, it will always cost the same.
This should not really be surprising: There is no reason for a single payer system (or a system that's equivalent to single payer) to have multiple prices for one and the same thing. The whole point of single payer systems is that the single payer has the bargaining power to negotiate the most efficient price up front. Paying more than that without need would be a waste of money.
Provided that your insurance is LAMal. I have Uniqa and private hospitals can charge me whatever they feel like. Uniqa has agreements with some private hospitals, so in the end it's not that bad.
For example, in Switzerland, each treatment etc. is assigned a specific number of fee points (Taxpunkte). This is multiplied by a conversion factor to arrive at the cost of the treatment that a doctor can bill your insurance. And that's that. Unless the treatment allows for variations, it will always cost the same.
This should not really be surprising: There is no reason for a single payer system (or a system that's equivalent to single payer) to have multiple prices for one and the same thing. The whole point of single payer systems is that the single payer has the bargaining power to negotiate the most efficient price up front. Paying more than that without need would be a waste of money.