Here's the thing, their "Traditional Computer" sales have not suffered at all in those years. There's only been a slight taper in sales since last year.
https://www.macrumors.com/2017/04/11...id-pc-decline/
And no, the desktop/laptop market is tapped. The majority of office productivity can be done on phone/tablets. The majority of "pro" work can be done on laptops. It's been a trickle down effect. Desktop computers are like the workstations of the not so distant past, which are like the servers/HPCs of an earlier era. Deal with it.
e: Think of it like this. Even if you have a use for large screen sitting on top of a desk, in 10 years what do you think will be connected (probably wirelessly) to that display? It'll probably be your phone .