Well, they've never actually gone away. Here we have a perfectly nice, simply patterned Fair Isle yoke sweater, knit in 1985 of Germantown wool purchased from Super Yarn Mart (anyone remember that place?):
Another view, showing the fair isle "floats":
And yet another view. It's hard to tell from the picture, but the dark areas are actually navy blue and forest green. My colors didn't have enough contrast, but still looked lovely closeup.
So what's the problem, you ask? MOTHS!
This sweater has lasted very nicely until last summer, when the dreaded winged beasties laid their little progeny on it, which hatched and MUNCHED holes all through this lovely sweater. Grrrr! The lesson? Wash all your woolens in Eucalan, and liberally equip your closets, drawers, etc. with cedar eggs! Don't let this happen to you! This has been a public service announcement from Knitters Who Should Know Better, Inc. Have a nice day.