If it was, I think we’d see as many new browsers as we do independent small game engines.
I suspect two things: it’s so poorly defined that we’ll have to accept this to accept new browsers, and that we will have to blatantly ignore it in order to create a simplified standard alternative layout algorithm.
People have Internet Explorer a lot of crap for being non-standard but there is no standard. All the intern projects like WASP did absolutely nothing to make CSS well-defined.
It just created the industry expectation that we’d all copy each other to fill in the gaps. If you read the codebases of the major web browser engines, it’s clear they do this in small but meaningful ways that would otherwise break various layout properties.
So I say screw it, since the people at Google basically hijacked web standards and refuse to give us popularly asked for features (check the web standards issue trackers for years-long open feature requests) just ignore them.
Make people bend the web standards to what you want them to be and then rally people to use your browser for fun and the love of using technologies that don’t hate you and abuse your expectations of privacy and the value of the hardware that you buy.