Site owners have incentive to run this proxy so they're not marked as a mining site OR to circumvent the X% fee that coinhive/other cryptocurrency pools collect.
So the adblock/ublock origin fixes will only work until site owners decide to start proxying. IMO search providers should penalize sites with poor performance (as they already do) and site owners are penalized if they suck the consumers CPU.
Is that not currently the case with ads, and addressed by blocking certain scripts/elements even if they originate from the same site?
I'd also suspect that it'll just lead to different ways of detecting miners (e.g. fingerprinting the behaviour of mining algorithms, or just blocking scripts that use more than a set CPU budget by default).
Detecting a similar script should prevent the proxying from working, but if the script is bundled into the main JS of the site (as many sites do now) it would be basically impossible to stop w/o blocking JS altogether.
Not sure if browsers can fingerprint script execution patterns, that's way further down than I go.
Script blocking will probably work most of the time, just as blocking certain urls gets rid of most ads.