Michael,
I beg to differ -- somewhat
Certainly, with today's papers and variable contrast control, developing to tailor a negative to a certain paper grade is no longer as important, but one can still pretty easily overdevelop a contrasty to the point where even the lowest contrast setting for VC paper won't deliver a decent print (or will, but only with difficulty). And, it's still easy enough to underdevelop a flat scene to the point where the #5 filter won't get you the contrast you want. Recognizing a) what you want from the final image and b) situations where your "normal" development time just won't deliver a negative that prints well is what the "develop for the highlights" adage is about. Sure, we have a larger margin of error these days, but the advice is still relevant.
FWIW, I've had difficult negatives to print at both ends of the contrast range in the last year; one with extended development that still almost didn't give me the contrast I wanted (had to break out the #47 filter for that one) and one that need a lot of dodging and some flashing despite my (SLIMT) N-2 development scheme. If I had just developed everything "normal," I'd have never been able to make prints from either of those negatives.
I honestly believe that we're often simply trying to be too precise with the Zone System -- more precise than necessary anyway. We can certainly be a lot less finicky about exact development times. But let's not throw out the baby with the bath water. There's still a lot to be gained by developing more or less when the negative would otherwise not fall within the window of printing contrast controls.
Best,
Doremus