I don't see this as a major problem since my nearly 4 year old computer is still working fine for most of my computing needs. Computer chips are so powerful now that they don't use a lot more than older computers didn't use.
The problem here is a bit more insidious than you might assume at first glance. The reason you can buy a motherboard for $100 which has close to a thousand individual components soldered to a 16 layer board is because a manufacturer invested tens of millions of dollars in a highly automated manufacturing line that could turn out millions of them a month, and all the connectors on them had injection molds made because billions of connectors would be needed, and testing companies built amazing bed-of-nails testers that can run 25,000 tests on that board.
When I was at NetApp our partners built systems for us (so called ODMs) to our specifications but in the thousands, not the millions, and our motherboards that had a similar complexity to the ones that Gigabyte or ASUSTek could sell cost us $800 each. Smaller runs, those in the hundreds, are like $2,500 to $3,000 each.
The lack of buying is taking the oxygen out of the system. These guys are cutting costs where they can, but there will come a time in your lifetime where buying a cost effecting "PC" class machine out of parts will be very very hard to do, they just won't have the volume. A new TV with similar smarts? Still cheap. But a desktop machine?
They call them economies of scale, when there is a scale, when there isn't they don't work so well. Factories in China are starting to switch over to making systems for server farms, not individuals. Amazon, Google, Microsoft might by 50,000 at a time. You and I, not so much.
We are on the leading edge of that change. I have a sense that it is going to be a fairly dramatic change.
Servers have been moving in the other direction all my life, becoming more and more like your commodity desktop. My dad worked with mainframes; when I came of age, SUN sparc was still a thing. As far as I can tell, as time goes on, the server stuff starts looking more and more like the consumer stuff.
Hell, half the low-end server stuff these days has a built-in APU, and there's a lot of discussion on how we server types can use that.
That said, yeah, if you doomers are right and people stop buying desktops all-together, your 3x-4x estimate on cost multipliers /for the motherboard/ isn't unreasonable.
Personally? I think the reason why old computers work fine right now is that everyone who used to spend effort writing new software to make your PC seem slow is now writing new software to make your cellphone seem slow. The thing is? I think this will pass. This is the first wave of "wow, pocket computers are actually useful!" which is cool and all, but I think that we're approaching the point where we are going to run up against the fundamental limitations of the form factor.
But yeah, that's the thing; until someone gets around to writing new software that makes your PC seem slow... PC makers are going to hurt.
Interestingly, check out AMDs CPU roadmap:
http://www.amd.com/us/press-releases/Pages/amd-unveils-2013j...
Looks like their low-end server chip is going to be an ARM.
This is consistent with the idea that the volume (and thus the innovation) is going to be in the mobile arena.
Of course, it could also just be a desperation move by AMD.
The more components that are integrated into the chip, the less there needs to be on the motherboard. Even better, all the high speed stuff can move onto the chip, making motherboard design easier. How long until SoCs come with RAM on die? Could you get away with a 4 layer motherboard in that case? So whilst you may lose economy of scale on the motherboard side, I think you will gain it back via integration, however, you will lose the ability to customise.
True but if the SoC was advanced enough it can make customization unnecessary. After all a phone or tablet or laptop or a desktop or a server is just a computer with some processing power and memory. Old super computers can now fit on a Samsung Galaxy Gear. Add more of the same to the SoC or make SoCs of varying specs. Who needs customization in such an environment.