As a developer you will probably understand this. There are steps you have to take to properly implement developed code. First, you have to have a spec, then you implement against that spec, then you test the implementation against the spec. The W3C has created several specs, and Browser developers developed code against those specs. Sadly it’s the third part that falls down. The W3C did a great job providing tools to validate HTML, CSS, and other specs for the web development community at large, but they haven’t done anything to validate there specs for the browser developers that I know of.
If Microsoft ran pages through IE and saw glaring errors because it didn’t render code correctly, maybe they’d have something to go on. Similar to automated test suites. Give them a path to properly implement and the tools to do the job right, and it might benefit the developer community. Maybe the W3c doesn’t need to be more open with the “web development” community but more to the “browser development” community.