"Prices have dropped a lot since the '07-'09-ish years of the hobby..." <--- pump the brakes
Everything collectible dropped in price during the big recession. It was the worst economically since the great depression. It has nothing to do with people dropping in or out of the hobby. That's 10 years ago too! Euro prices have gone up since I've been searching German eBay over the last year or so.
Honestly, the more I think about it, prices are a terrible gauge of the number of people in the hobby.