IMO the most effective consumer cost control is competition. An actual, non-corrupt, free market where customers are not locked in and there are more than just a handful of providers generally results in low prices.

We do not have this in healthcare. Providers form cartels - at least in Northern California, this is so bad that the state AG is investigating (not very effectually) [0]. Customers generally can't even tell what a provider charges, so there is no price competition. There aren't many insurers, and they compete on so many incomprehensible dimensions that customers can't usefully choose. (And the most useful thing customers can look at is the network, but see the above issue with provider cartels.) Pharmacy benefits are highly corrupt and incomprehensible.

[0] We have Sutter Health, UCSF, Stanford, and Kaiser. There is very little in the way of independent providers left. Sutter Health in particular has aggressively merged with any available competition.