Page speed is already taken into account for ranking.
Google is never going to do that drastically though .. better the result people are looking for even if the page is slow than something fast but barely related.
I am not sure what else they could do in that regard, and the ecosystem has been moving towards more and more bloat since pretty much the beginning.
I am all hears for other solutions to page speed, especially since AMP is tailored to a specific use case, I just don't know exactly what would be enough of an incentive.
> both ?
They are competing objectives, so which has the bias is indicative of business priorities.