Earlier quoted context omitted.
The vast majority of terminals in the US use chip, but I doubt the US will ever require pin numbers for credit card purchases. It's just too inconvenient. Banks are willing to eat the tiny reversed transactions in exchange for making the payment flow more efficient.
“Banks are willing to eat the tiny reversed transactions…” Banks? A chargeback goes to the business.
And the public eat the inconvenience of having fraud transacted on their behalf.
Why merchants don't insist on C&P isn't clear, though I suspect that distributed liability, ignorance, disaggregated political voice (see Mancur Olson's "Logic of Collective Action" https://www.thoughtco.com/the-logic-of-collective-action-114...>), as well as asymmetric cost/benefit incentives between specific retail points-of-presence (store managers and franchise owners) vs. corporate purchasing and policy (see the McDonalds ice cream machine fraud https://www.wired.com/story/they-hacked-mcdonalds-ice-cream-...>. Multiple HN discussions: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...>.