It would have made a change if it was more properly communicated and had a stricter penalty. Really, if those sites where warned for having a few MB's of tracking js or unnecessary assets by google and facebook they would have changed. The problem is that the warning was just sent out as blogposts, not as a drop in SERPs.
AMP was for mobile. That prior change was for desktop. This new change is for mobile. Ergo why didn't they start with an SERP boost for fast mobile pages period rather than the AMP system.