ublock origin won't help you blocking the ad elements if the entire website ui is rendered in a canvas (already starting to happen thanks to some frameworks like flutter) and can't block the ad logic if it bundled in the wasm along with the rest of the app. It might still able to block the requests, but they're starting to serve the ads from the same domain that serves the website so it can't be blocked without breaking the website itself, and might begin to serve those over websocket so adblockers can't block it by url path. With javascript, an ad blocker might still be able to monkey patch the ad logic on runtime to break it, but with black box like wasm I'm not sure if such thing is possible.

Once tooling and frameworks make it easier for average webdevs to use webasm, I'm sure ad companies will begin to offer it in their ads sdk. Thankfully most websites with ads are still care about SEO so at the very least we can be sure it won't happen anytime soon, unless something changes in how google works that could enable this.