The desktop computing model (and the client/server model) is in its dying days, with the exception of certain specialized applications, and a few holdout companies and industries that will stay with desktop computing for much longer than the mainstream. But for the most part, I feel that desktop computing is practically dead in the consumer space, where mobile and Web have become the norm. In the business space, I think most businesses have only one or two applications (other than Microsoft Office) which the bulk of their workers count on and that keep them tied to the desktop model.
I know of very few developers doing non-Web development for business applications at this point. I give the desktop model five years at best for mainstream business usage.
How long will desktop computing matter?