> I don’t get it, do US citizens prefer being defrauded over what is perceived as a slight inconvenience?

The general idea is that if the conversion rate drop of a given security mechanism is higher than the average fraud rate, it doesn't make financial sense to deploy it.

However, at the industry-wide level, this is a pretty classical coordination problem, in that conversion rate only drops because there still is a simpler alternative around unless all merchants and banks were to enforce 3DS at the same time. If there's nothing more convenient left to move to, users will for better or worse have to learn the new, more secure thing, and conversion rates will go up again.

This is what the EU has done with mandating 3DS for many payments, but even there regulators have recognized that a 100% coverage is counterproductive, and there's a sweet spot somewhere in the middle.

As more evidence for the same general idea: US credit cards don't have PINs, because any individual bank introducing them would see a huge drop in usage rates since customers would just use their competitor's card without a PIN instead. In other markets, all cards have PINs (whether due to regulatory invention or card network incentive), and people have just gotten used to them.