I don't think that model building is dying.  I live in a relatively small Texas town, it is a college town.  When I go to my local Hobby Lobby.  (No local hobby store.  Town isn't big enough to support one.)  There is always a college aged kid checking out the kits.  I think that they would sell more of them if the prices are lower.  Hobby Lobby marks everything up quite a bit, and then occasionally offers 30% off sales.