I agree with the conclusion, but not the logic.

A much more likely cause for IE supremacy is an established set of enterprise "web" applications, where these (badly written) "web" applications are so broken outside IE that they might as well be Win32.

If executives sank money into applications that now run the business, and find that IE keeps those applications running, they're more likely to establish an easy policy like "IE only". They are not likely to spend money to "fix" the "problem" that non-IE users "created".

As ideal as it would be to inform executives that it is Microsoft's broken code that actually created the problem of bringing in new browsers, I guarantee they won't see it that way.