More than that: they see non-Microsoft web apps as a threat to their ecosystem. They will do everything to fragment the market in order to make it as hard as possible to deliver cross-browser applications without making IE clearly inferior to the competition. Using that with companies that standardize on IE for their corporate desktops and making IE just incompatible enough, they make it harder for companies to migrate away from Windows because core corporate web applications require it.

Several web applications in the company I work for require IE. I have Windows in a VM for that.