They can already do that, and are doing so, through Search, Analytics (maybe), ads, etc. That war is long lost.
Although your point is well taken that there could be ways to sneakily track users eventually despite the aforementioned measures, and potentially even without javascript being required (though I doubt that share of privacy-concious users will ever raise significantly - most people simply don't care).
Their AMP cache happens only on their search service. They already know which links you click... having an AMP cache on top doesn't give them MORE information than they already get. The use of that cache also make sure the website doesn't get more information because it's preloaded.