For many memory intensive operation, this is incorrect since by that logic, Apple’s chip should use far more memory due to having quarter as many registers for those purpose. (32x64 vs. 32x256)
Most processors have cache memories for reasons you stated.
Disadvantage of said system for Google would be the fact that if you do that, people can skip ads much faster and they won’t be able to do any tracking of interaction at all. For advertiser’s point of view, that would be just worse version of TV commercial.