What's the history and status of ASPA? As far as I can see, it's a fairly active draft with the IETF: https://datatracker.ietf.org/doc/draft-ietf-sidrops-aspa-ver...
It says it's on the standards track, but it's clearly quite new. How well has it been proven out? This page from Hurricane Electric shows <3% adoption: https://bgp.he.net/report/rpki_and_aspa