Regarding Quirks mode: HTML came with a promise, namely that any documents written would be universally readable for a long time with minimal application requir

Regarding Quirks mode: HTML came with a promise, namely that any documents written would be universally readable for a long time with minimal application requirements. This is probably the single most important feature that made the Web such an important and successful publishing platform. (No, it was not invented for short-lived social media content.) Documents, once published, should be accessible without further maintenance. (This is, why you should think twice, when introducing yet another web standard. You will have to maintain it for a very long time. Think of standards as conceptual debt.) There are so many important and even crucial documents, that would become unavailable. E.g., if you are interested in computer history, you know what I mean. About every document that isn't just copy-and-paste content is behind a http-only browser warning and written in a standard that dosen't comply with html5. The premise that everybody would be able to republish the content is somewhat mistaken. What's the way around this? A common effort to preserve these documents, maybe by an automatic translation layer? Well, this is quirks mode… PS: Now one could suggest to have special browsers for legacy content. But, how would this work out with any links? You were to break the principal premise of the Web by introducing a fundamental schism. Now there are two kind of webs, and you'd probably need two kind of links.