I actually have read a chunk of the relevant TAOCP, but didn't mention it because the comment was already kind of long. I remarked to a friend the other day that it's kind of funny that we've a little bit come full circle on asymptotic analysis in that we are now counting FLOPs, and it is not a little bit like what Knuth does here. :)
I think this needs the use of a CAS (Computer Algebra System, like Mathematica) to calculate the runtime of some code relative to different choices of computer architecture. Then it looks practical. Could even be added to IDEs. But without the help of a CAS, few people would attempt this, because it would be too tedious to do by hand.
