It is surprising to me how blind Google is to the second-order effects of this is. Suppose that this model of rendering pixels to canvas is a success. Suppose it is adopted by various content serving systems like WordPress, JavaScript frameworks, etc. Now Google Search has nothing to index! The whole web just became completely unsearchable. Google Search, and all web search as a concept, becomes mostly useless.
You might think that Google assumes that they’d be served special content to index, but I remember the shenanigans that people used to pull with serving the Google bot one set of content and actual page visitors other content, and how Google has to continually fight against this to preserve the relevancy of search results. If canvas rendering becomes normal, Google will have no way to fight against this anymore, and Google search results will be dominated by links which does not contain the promised content.
It’s possible that Google thinks that Google is big enough that nobody will opt out of being searchable by Google, but consider Facebook. Facebook content is basically impossible to find using Google, and everybody wants to be the new Facebook, right?
As I see it, the efficacy of Google Search rests on a few premises which were true in the 1990s:
1. Web content which is created without indexing in mind will be able to be indexed by Google.
2. If web content creators have indexing in mind, they want Google to index the content, and the path of least resistance will allow Google to do it.
3. If web content creators want to play funny games and serve one set of content to Google and other content to site visitors, this is difficult and requires playing a constant game of cat-and-mouse with Google.
If canvas rendering becomes the new thing, all three of these things reverse and becomes false. How, then, could Google Search stay relevant? Why would people pay to advertise on Google if Search becomes useless? Especially when Facebook ads exist, and Facebook is where people spend more than 90% of their web time on, anyway.