Earlier quoted context omitted.
The biggest pothead team at Microsoft was the Internet Explorer guys. So if you want another 20 years of calculating bounding rectangles incorrectly, by all means let's get the rest of the company baked.
Of course, the old IE box model is what everyone else overrides the default to match nowadays. Maybe they were on to something!
¹ See: XMLHttpRequest, innerHTML, box model, CSS filters, CSS behaviors², VML, etc
² Well, behavior: was probably a terrible idea, but it did allow hacking oldIE to support an awful lot of CSS3.