There's nothing preventing adblock from working on amp pages. Amp is currently a mobile only thing, and most users on mobile are not blocking ads.
I don't know where this myth comes from that amp is all about blocking adblockers: amp pages require a markup that specifically tags ads as ads and prevents running scripts after page load. The only two adblock-defeating techniques are to disguise your ads as content, and re-insert them after page load, both of which are rendered impossible by the amp spec.
> Amp is currently a mobile only thing, and most users on mobile are not blocking ads.
Most users anywhere are not blocking ads, adblocking by its nature as a non-default option and something you have to know how to do will most likely never be the thing that "most users do".
Worldwide, there are almost 150m more mobile adblock users than desktop adblock users. The trend of only blocking ads on your desktop is largely a North American phenomenon.
I can't speak to whether or not AMP is designed to try and stem this tide or not, but I can say without a doubt that mobile adblock is exploding, especially when considering the worldwide market, and that publishers are probably very nervous about this.