My impression of IE is that Microsoft stopped developing it right at the point when they realized "Oh shit! If this gets any better, it could replace Office!"
And no, I'm not speaking on behalf of my employer; it's just my personal opinion.
When a single someone can make a tiny javascript file that fixes nearly all the rendering problems in your browser (Dean Edwards, IE6.js, IIRC) then it starts to look really bad for your abilities as a multinational megacorp that's supposed to employ some of the finest programming minds.
My impression is that it's still a pretty small team, if only they'd done it consistently over the last 10 years.