Seems to me that a lot of this is still in basic HTTP. We have 402, and HTTPS. Couldn't we write up a set of APIs on top of HTTP that lets us send crypto or even USD?
Sure, that’s the easy part. The hard part is to convince payment processors to use it. There are too many economic incentives to going your own way.
The incentive for a generic data interop framework with logical and cryptographic proof (which was the intent of the semantic web) would be arguably high enough that adoption would be universal (similar to HTML). Alas that too hadn’t been true, yet.
