Gary, I would ask not just how many serious King & Country collectors there are, but how many Military Miniature collectors there really are, and how old are they. I think the hobby is 'greying' like a lot of other traditional hobbies, from stamp collecting to model railroading.
I have had this conversation with Andy, Thor, Rick and countless others at the retail and manufacturing end.
I can really tell this at shows when I see who is purchasing the gloss painted traditionals. To take it further, fellows buying the unpainted plastics are younger...baby boomers in the 40s! There will always be collecters of everything, but unless we do something to bring younger folks in, some one will be the last man standing with a very, very large collection. Imagine the enviromental impact on the town where that collection will be!
Perhaps the younger people that collect and paint "Warhammer" style figures will eventually step up to replace some of us. Hopefully they will realize that real history is every bit as intersting as fantasy!