It’s always astonishing how I can get a fully itemized vet bill right after a visit and pay for it. Meanwhile going to the hospital is like “well gee, let’s submit to insurance, see what they’ll pay, we’ll readjust prices and then come back to you in a few months.”

Yes. Prior to insurance. Insurance is the reason prices aren't transparent; insurance companies demanded discounts, so providers raised their prices to then say "you're saving X from list". But not every company had the same bargaining power, and individuals had none, so the actual desirable price to offer couldn't be made broadly available. With a hidden price (so no shopping around), that is discounted at wildly different rates (so no meaningful way for third parties to track it), and a necessary service (so no just avoiding it), in a private for profit industry, of course it skyrockets.

Our options are either to mandate publicly available price lists that are adhered to and hope the market pushes things downwards, mandate prices, or socialize insurance (so that the sole representative of everyone can negotiate the price downwards using the leverage of the provider risking losing most if not all their clients). Or, you know, keep doing what we're doing which is working so well (/sarcasm).