I agree with you. I guess the need for more speed would come from using larger files or a larger number of files in whatever work flow. For day-to-day, I think we reached all the speed we will need probably 4 or 5 years ago. At this point, pretty much any machine you buy is overkill for word processing and web browsing. What will drive the need for more speed is gaming, video editing, maybe image editing, 3-D rendering, etc.
I know that it is ridiculous to say this, but I think for the normal person we are at the point where speed increases no longer matter and what we have now, and have had for several years, is all that will be needed. I mean, in all honesty, my 2010 iMac with an SSD would be plenty fast for the vast majority of what I do. In 2010 I would not have been able to say that about the computer I was using in 2002.