Ahh, I see your point now. Things might have progressed faster, but LED's have come along way since the 70's. That's only around 30 years which is a lot less than the 100+ years the incandescent bulb has had.

I don't think it has been held up, but recently competition has help things along a bit. The CREE LED that has been mentioned is a real breakthrough, and is very close to catching and overtaking fluorescent tubes. We also have Philips (maker of the Luxeon), Nichia, and OSRAM developing ever better LED's, so it anyone's game right now. It's not a 2 horse race like the whole ati/nvidia or amd/intel thing.
Also, even tho tubes are most efficient right now, they do contain mercury vapour, which is very nasty stuff if inhaled. Something to think about especially if they are used in places such as schools and hospitals. Yet another reason to go to LED methinks.