I think the underlying cause is that there are just not so many kids of our age as there used to be, and our numbers are steadily falling
Looking at the avsim and flightsim forums, there seem to plenty of the young'uns asking questions about the sim, but they call it a game, and the questions show they don't know the sort of basics that every schoolboy used to know.
I think that might be behind the recent trend for commercial developers to present aircraft which are already well covered by others, freeware and commercial alike - the developers are chasing 'brand loyalty' in a market where most of the purchasers have never seen the plane in real life (F27s, Viscounts etc) and can't recognise the quality that some models have and others lack. Much the same would apply to scenery, and ES made some of the best. Unfortunately, for many of the young'uns something that does not instal simply, quickly and correctly, straight out of the box, will just be discarded , to the Too Hard basket, and then forgotten. That is NOT ES's fault. Not Earth Simulations, anyway...but if ES stands for Education System, well, you could be onto something there.