I understand the author's frustration, though I don't agree with all of his points. However, what is Microsoft's motivation for investing in WPF at this point?

I understand the author's frustration, though I don't agree with all of his points. However, what is Microsoft's motivation for investing in WPF at this point? If they don't improve WPF, will enterprise customers stop using Windows? Unless it moves the needle significantly one way or another, they won't do much with WPF. Besides, they have their hands full on other fronts.