PC sales (laptop and desktop) in general have been on the decline since 2010 or so and the margins in that market for players who aren't Apple are generally so low that the declines don't have to be that bad to really put a squeeze on manufacturers.

The iPad/Tablet market gets almost all the credit for this decline in the media but while I'm sure that's part of it I personally think the fact that we hit a point around 2010 where desktops and laptops were just plain good enough (truly good enough, not 640k good enough) for almost everything people normally do was as much or more of a factor than tablets. Short of having a machine die on you there are precious few reasons to run out and buy a new system anymore.

I'm a software developer, a hobby photographer who shoots in RAW and a gamer and even I haven't bought a new desktop or laptop in 4 years (and I used to be someone who would build an entirely new desktop system yearly with major upgrades 6 months in to boost it up).