I'm no authority but I can think of a few things that might affect it.
1) our workers aren't as good as they used to be, or maybe it's better to say they aren't as effective. There's no need for new hardware because software is becoming too simple in areas, and not pushing the limits fast enough in others. As an end user, the adobe line of products took a huge step backwards when they switched to their online versions of their software. Features that used to work fine, no longer worked. Things you really need to to your job (preview in after effects for example) removed because... "it's hard". Or, "the system doesn't work that way anymore." I'm watching Autodesk stagnate on a level I didn't think possible, charging big bucks for the same old tired shit. No decent new features, all wax and detailing. Game companies used to make things specifically for the PC which really pushed the need for a new graphics card or a new processor, but now it's all watered down to the mass production specs of the crappier console the game is also supported for. Skyrim (as fun as it was a times) was an ugly piece of shit compared to other games at the time, and it's not a surprise why. It was made to be console compatible.
2) The money is in small one offs and mass compatibility, not in huge boundry pushing projects anymore. No huge projects, no need for processing power. (And given the crazy hours I've worked in my life in computer based fields, they had this shit coming. I'm not surprised people want to be able to work from a tablet and say fuck it.) It's not just computer hardware though, look at tvs. Who has a 4k tv? And if they do, who is making shows for it?
I don't know, things feels way out of whack since I was a kid.