But work environments, software developers and gamers don't make up more than 20% of computing device sales. And most of those sales figures are for consumers,

But work environments, software developers and gamers don't make up more than 20% of computing device sales. And most of those sales figures are for consumers, so they are ignoring work places all together. Software developers might get by on a laptop, but most I know most prefer to have a desktop at home. That may be rather anecdotal evidence, but so is reading statistics wrong. And gamers, well, they sure value their customised rigs. Some of them might prefer consoles, but there is still a huge range of gamers preferring desktops over everything. Niche, perhaps, but just like there is some value to having a landline telephone (call a place rather than a person), so is there value to having a desktop. Most consumers won't care, I imagine. But that doesn't mean the desktop will go extinct. Regarding your a) and b); I am certain some businesses are moving to laptops and other non-desktop entities. But that doesn't mean all businesses are or will. It is most likely the lack of end consumers buying them that is reducing the total sales of desktops and not businesses.