Being on top of pingbacks makes no sense, xml-rpc is dead and a bad idea in a first place, also a lot harder to implement than just reacting to a ping + pretty

Being on top of pingbacks makes no sense, xml-rpc is dead and a bad idea in a first place, also a lot harder to implement than just reacting to a ping + pretty much incompatible with the pull concept. If they started there, they probably did not know trackbacks existed. Webmentions are no simpler than trackbacks, and to have them diverge for no reason makes everything more complicated for the engine. It is no straight-forward simplification at all, thus no good thing.