WASM is aiming to be fast enough to actually be capable of running a rendering engine. No more DOM for adblockers to look at, the pages may finally become canvases.
Right, but you can already do that. Serve the whole page as a SVG, or JPEG, or PDF. You can already embed ads inline. Or just plain serve them from your own server, calling them article.jpg instead of http:://ads.adcompany.com/advertisement.jpg .
The reason people don't do this, is because ad companies want control. They want to know exactly how often the ads are served and they don't trust you to serve their ad all the time and to all customers. Also they want to rotate it quickly. Finally, they want to track people. So the solution is to use remote javascript. 99% of ads work this way, even mayor news sites don't sell their own ads anymore.
In this scheme, you'd probably still have ads served from a third party server. And even if they obfuscated the domain name, you could still probably identify their blob and block it.
So I'm not to worried about unblockable ads. But you're right, they will try, and I am worried about sites becoming unusable because they will emulate browsers using canvas, poorly.
If you run your own rendering engine you lose accessibility. If you add aria tags to stuff in order to make it accessible, adblockers will be able to read them as well.
I don't think advertisers care about accessibility. Not the same companies that want auto-starting video clips in your browser.
As for the site owners - unless it's someone large enough to care, I think the usual choice between "letting a few disabled persons access the site" and "getting a few more bucks from advertising" would be quite obvious. If that question would even arise.
Don't most ad blockers just rely on media queries on the DOM? I imagine there's a lot of ways to circumvent those techniques when you are rendering raw pixels with wasm.
Those pixels still have to go somewhere in the DOM, and clicks on those pixels still need to be handled. Plus, there's nothing wasm can render that you can't render with uglified JS already.
I don't see how this necessarily follows from WASM.