sure thing boss.. for like the 15th year in a row microsoft is well on their way to becoming irrelevant, presumably to be replaced by macs and various linux dists.
as cbase said, what is going to become less relevant is the browser window. not the browser engine per se, but the browser as a discreet application that you run.
for years we've been seeing apps take the place as the premium way to deliver content on phones and tablets, and win8/chomeOS will push that trend even further, and will both include some os specific libraries that will break cross platform. but that doesnt matter, if there is money to be made, people will rewrite their apps