Kind of a software question, but why isn't nfc with asymmetric keys a thing? It seems like at best this is a custom javacard app on select expensive cards ($4 p

Kind of a software question, but why isn't nfc with asymmetric keys a thing? It seems like at best this is a custom javacard app on select expensive cards ($4 per card if you buy 1000 on aliexpress) or $70 for a yubikey otherwise. Is getting the signature time fast enough just impossible with current hardware/tramission power restrictions?