This is a very interesting proposal, but as a programmer and with my knowledge of statistical analysis I have to disagree:

The increase in computing power that you regrettably cannot observe at user level is a fairly minor quirk of the development; pray tell, does the user interface of your Amiga system's OS and your Dell system's OS look alike? The reason why modern computers don't feel faster is because the programs we run on them are wasteful and gimmicky. However, in therms of raw mathematics, we have 3D games with millions and millions of polygons, we have multi megapixel screens.

Statistical analysis is a breeze: Exponential regression on 5'000'000 data points is a blink of an eye; you can actually hold it all in memory at once. Raw numerical analysis can be done in paralell using general purpose GPU programming, etc. Your computer can solve your algebra problems faster than you can type them in.

So I fail to see why computers evidently being myriads times faster now than 30 years ago is an argument against intelligence explosion.