Relative numbers are UTTERLY USELESS when absolute differences are of this magnitude. It is a well-established fact that single-thread x86 CPU performance has plateaued over the past ~5 years.
Try not to use words that are absolute. "Utterly useless." If you want to look at it that way literally everything aside from food/air/water is useless. Value, is in the eyes of the beholder. I think its ridiculous people put more value in a shiny stone that has limited exceptional qualities and goes on your finger. I'd call that useless, but lot of people don't.
My point is talking in that manner adds nothing useful to the discussion.
We can do better in the single threaded department. Do better as in, we can use them. Because vast majority of the people do not pursue the activities enthusiasts in Anandtech forums do. If you eliminate game playing you eliminate most of the companies and most of the revenue generation for all the companies. So with most buyers its always the responsiveness that matters.
The human senses are quite amazing. Once you get used to a speed that seemed fast enough, it no longer feels that way. People used to complain about 60Hz monitors. Now some people don't like handling anything under 120 or even 144Hz. I personally think anti-aliasing settings are an absolute waste in resources considering how little of a difference it makes(when you are playing the game) but there are a whole class of people arguing about the technical differences between AA modes.
Not to mention, parallel programming isn't just about just shouting at the programmers to do so. That would be irresponsible. When you could do more useful things like, making
better games. Meaning single thread performance is the only realistic way to get consistently faster performance.
In fact we can do better than 0.5x seconds. I believe the true no-need-to-buy-another-computer era would occur if the industry actually gets to have persistent memory(like 3DXPoint) and we get instant boot/load computers.