Thorny,
You are generalizing. It sounds as if our hero is actually interested in shooting the gun first, rather than simple speculation. Hence, to deny a whole segment of gunmaking is a bit foolish, in this case. Rest assured, there are German, Italian, Belgian, French and Spanish makers who can build the equal of anything built today in England. The reason it won't sell for as much is it won't cost as much to begin with.
As to the Americana pieces, actually shooting and hunting them isn't all it is cracked up to be. 100 year old stuff has it's limitations, and ignoring that will cost as much or more than the "right" shooter would have in the first place.
Lebeau Courally, Hartmann & Weiss, G. Granger, Fabbri, there are others, and it's all good.
Best,
Ted