I think it's probably just a matter of instructors adapting to demand. Equipment has definitely changed. Even at small, icy hills like Holiday Valley in NY, most skiers I see taking lessons are showing up on gear that, just five seasons ago, would be considered totally inappropriate(or unsafe) for the conditions and terrain. It is now extremely rare to see anyone on sub-80mm skis, regardless of where you are or who the skiers are. The rental skis are even changing. Beginners are now being put on wider skis as well.
IMO, this entire shift was dictated by marketing and image, not reality. Eastern skiers didn't wake up one day and have a hunch that they should really be skiing ice on 88mm rockered designs.
Nobody is even producing skis under 72mm, outside of race skis. The average width today seems to be around 80mm and growing. IMO, the industry will come back to sanity and this will occur when the wide/rocker fad starts to wane, which all fads do, and many skiers realize something is not right with their current selections.
Skiing my race skis as my everyday ripper helps me stay focused on what really helps. To be honest I love the trim 65mm waist and after a few days on those my other skis in the quiver feel bulky and slow. I'm not sure how twin tips became a fad outside park because to be honest I do not find a ski that cannot hold edge an exciting tool to ski. Skiing is all about being dynamic, and that is the reason they produce skis to adapt to different and changing aspects of the sport. The real problem is a significant rise in narcissism; my generation is all about coats three sizes too big left unzippered and snow pants belted at the knees.
Let's be honest; I laugh every time I see an old timer on 220's wearing a purple one piece with the pink goggles. Needless to say, I laugh even harder when I see an open winter jacket with an XXXXL basketball tee on top, baggy pants (all this is ridiculous color contrast to each other).
Suffice to say there is always a population of skiers of all ages who remain true to the original purpose of the sport; to continue to ski for passion and because we love it. Aesthetics are all well and good but when the image is more important to some than the activity, you really are missing out.