That's naive. E.g. SIMD is here since a good time and going to stay. So are GPGPU, with now quite similar architectures for tons of chips.
And Computer Science can actually be about science for real computers, and computers are not 8086 nor PDP11 anymore, and have never been a turing machine. So there actually is some existing generic CS and ongoing research that cares about cache effects and so over. Maybe it is applied CS if you want, and some kind of pure CS should not care about that, but I really don't see what should be the criteria to decide which is what anyway, so IMO there should not be any (but I do not mean that all research should care about e.g. cache effects, just that it is not really useful to attempt to distinguish between those which do and those which don't).
We don't teach advanced math by only showing what was done at e.g. the beginning of algebra. Neither should we stick to only basic subjects in computer science.
I wasn't very clear on that point, but didn't mean to suggest it be the same textbook. These other topics deserve courses and books of their own. The algorithms lecturer should be careful to emphasise the limitations of complexity theory though.
> that knowledge (at least once you attach numbers to it) has a shelf life, and not a very long one
Plenty of long-lived principles to be learned there, even if the particulars change over time. Caches are still going to be around in 10 years time.
Which would have the positive knock-on effect of the textbook being sufficiently obsolete every year or so that the students could no longer trade it in for credit, saving the bookstores money!
More seriously, that knowledge (at least once you attach numbers to it) has a shelf life, and not a very long one. Teaching big-O analysis means the knowledge is timeless, which any good theoretical knowledge is, and moving more towards practice would force the professors to keep on top of the state of the art, and the state of the mainstream, of hardware design in addition to everything else they're doing.