Nostalgia plus funding equals collecting. For older collectors, fathers, grandfathers, and uncles had stuff; they played with it and listened to stories, and watched films like "Combat" and "Mash." At a certain point they wanted to own the things that they remember fondly and finally had the funds to indulge.
Today's youngsters (Millenials, GenXers, etc.) play video games and watch movies. At some point they, too, will want to own things they remember from those games and movies, and possibly from fathers, grandfathers, and uncles (hence Vietnam stuff and Middle East war stuff, Desert Storm, OEF, OIF). Once they have the funds, they'll start acquiring stuff.
The demise of the surplus stores plus fewer shows will push many of them on-line; ebay will become less important and other forums (Instagram, Facebook, Craig's List, etc.) will become more used (I say that because ebay's business model seems to be turning away from auctions and more to buy-it-know and away from old stuff and towards newer things that more people want).
I also think that new collectors will move away from buying a lot of items and move to smaller collections with higher end items; unfortunately this will open the door for more fakes (or reproductions pushed as real) hitting the market.
And don't rule out the unanticipated; a super movie about WW1 may hit the theaters and DVDs, and drive collecting WW1 helmets up, much like "Saving Private Ryan" drove up the desire for M1911/M1911A1 pistols. Prices seemed to double overnight, and pistols manufactured by US&S more than doubled in price (and still remain high even today).
Edited by thorin6, 17 May 2018 - 01:38 PM.