It is because spec or implementation quirks and bugs will get papered over to save time and effort. The standard will become less exact over time and point to t

It is because spec or implementation quirks and bugs will get papered over to save time and effort. The standard will become less exact over time and point to the source code of Chromium "just do it like Chromium, here's the link to the code", instead of having a clean spec with multiple standard implementations. Firefox will suffer even more as this happens. Its like Office Open XML (OOXML) standard, where the standard literally said in some places "how Word/Excel 95 implements this feature".