It may end up being the same thing. Publishers reluctantly used AMP because of the carousel placement. Depending on the effort to revert, removing the incentive may effectively kill AMP.
Publishers absolutely want to take people to their main site, not the AMP facsimile. If Google actually do what they say here, this will kill AMP.
You are very optimistic about publishers actually making the websites fast. (like just how they did before AMP existed).
Disc: Googler but not associated with AMP whatsoever.
Publishers have shown that they can devote developer effort when there is a clear ROI. Google just need to make the criteria for inclusion in the carousel understandable and measurable.