And, under ideal circumstances . . . its gonna be hard to beat Assembler. (Slower to market . . . perhaps . . . but faster for you the next 20 years as you run it.)
You may be right, but I wouldn't bet on that. First of all, it's not unheard of for a CPU architecture to die in 20 years, but that aside: It would be interesting to take an x86 assembler program written 20 years ago and run it on modern hardware, then perform the same experiment with a C program recompiled with a modern compiler.
The 20 year old assembly program would be optimized for a 20 year old CPU architecture (and essentially running in backward compatibility mode), whereas the C program would be optimized for the current architecture. I'd wager you'd see far greater improvement moving to the modern CPU in the C program. Whether it would be faster than the assembly program would depend on what it did, but I would think that in many cases the C program would be faster, even if the assembly program smoked it 20 years ago.