MadMike,
I think there will be a future :-)
First of all, thanks to internet and international Post, it is now easy to have contacts in Japan and obtain items that were previously unheard of outside of that country. Yahoo Auctions lists over 4000 offers just in modelgun category. This is a lot, the number is higher than whole Airsoft or "Military Weapon-related" categories on similar Polish site. I do not believe that this market will vanish, even if new production is stopped. Heck, we are still buying 20-year old replicas!
Modelguns are much more limited, as they are not very "practical". With airsoft replicas you can play games, interact socially, pimp them up, collect variants... all of that starting from very low prices. That makes airsoft very available and affordable, I don't believe modelguns will ever reach that phase. Market is pretty limited - there is less modelgun retailers in Europe than airsoft retailers in city where I live. We form a small forum, yet we are still active here! :-) I would not say that modelgun collecting is more "elite", it is just different than airsoft, blanks or even real weapons.
Next - modelgun companies have already perished in the past, some of them do not exist anymore, some do not produce modelguns. Those that exist often no longer have molds used for older models and cannot reproduce them. Even with all those problems the industry is still going forward. Marushin is experimenting with new types of hybrids, releasing kits. Shoei reproduces their models turn by turn. Hudson recently released STEN. Scale is maybe not huge and it definitely lacks completely new models, but it is fairly good.