Ditto for designing graphics and video editing. I need a quad core computer, a BIG screen, mouse and keyboard. No way you can do that on a tablet.
Tablets will become the mainstream system. I know a lot of writers who have gone to Ipads with bluetooth keyboards as their primary machines. A Core i7 with 8 gigs ram and a terrabyte hard drive is massive overkill for web surfing and word processing. These days, it may be overkill for many formerly high-end purposes.
Higher end computers will remain, but they will become more or less niche products. I’m a photographer and video guy, but I’ve gone from a 12 month purchase cycle to an 18 month cycle to a nearly 5-year cycle as computers have become more powerful. I still have stacks of external hard drives full of photo and video projects, but a Core 2 Duo or G5 is still sufficient for most things.
I just replaced a 5 year old laptop due to wear rather than lack of processing power and my 2004 PowerMac G5 is still going strong.
Computer companies are facing a new reality, since folks are less likely to replace machines until they actually break.