Instagram, Facebook, Pintrest, Youtube apps are already this thing. Tens of megabytes embedding a browser to view web content. Their traffic covers a significant portion of the entire web. All of these have a lot to gain from rendering ad blocking impossible. And for keeping people on their "platform", inside their walled garden. Right now they are shipped as native apps, which the web version will nag you about until you install it. I don't think it is so farfetched that they will try to use WebAssembly for the same.