I think it's mainly because they aren't forced by regulation.

Germany is another first mover with decades old banking systems and standards. German banks also dragged their feet supporting SEPA Instant or they added additional fees so that barely anybody wanted to use it.

Then the EU stepped in with regulation: If you support classic SEPA transactions, you also have to support SEPA Instant for the same price (which is almost always free for retail banking accounts). And suddenly banks did.

> the price structure of this infrastructure has wormed its way into everything in a way that is difficult to undo without causing high-visibility inconvenience for low-visibility benefit

I think the “recent” change allowing merchants to pass along the credit card fees is a step in the right direction.

I think a lot of people would still choose fraud protection for the extra costs, though.

The US also has incredibly pro-consumer regulation over credit cards, compared to most of the world. There is no such thing as "not protecting your card" as a way for the bank to get out of paying for credit card fraud. Legally, you are liable for the first $50 of unauthorized charges, and that's it (though most cards will cover all of it).