IE is just frustrating. Very few developers enjoy their jobs because of its unwillingness to comply with suggested standards. It's developer-base is small. It's not easy to develop addon's for (Just ask Sven with his find-as-you-type).
If you think about it, making it easy to develop add-ons for IE is the worst thing you can do for the IE profit center (if there is such a thing). People will start calling MS tech support eating up profits.
Maybe the IE team is like cicadas we get here in Ohio. Only coming up from underground once every 17 years, make lots of noise, then gone again.