Because that would not achieve the actual goal: to get people to stay on Google's properties, preferably without an ad blocker installed.
Note how over time more and more of the things that Google used to simply point to are served by Google directly. AMP is just another element in that strategy.
Interesting because actually it was AMP that pushed me out of Google properties, to Firefox for Android with uBlock and DuckDuckGo and I'm planning to stay using this setup even though Google's engine is better (minus AMP).
Note how over time more and more of the things that Google used to simply point to are served by Google directly. AMP is just another element in that strategy.