This future seems inevitable. The only sites you'll be able to actually use without some custom web assembly renderer will be those which don't serve ads at all now - wikis, open source projects, non profits, corporate web sites, etc. Any site funded by ad revenue will effectively remove itself from the web and into its own web assembly app instead.

We might even see the rebirth of something like AOL, a meta app that will be a portal to render content for others who want to use the platform. It might even just be an upcoming version of amp, or a new feature offered by Facebook or cloudflare...