I appreciate, even as a Damn Yankee (who grew up close to the MD Line in The Queen City) all the history, and yes, both the War Between The States and later WW1 brought us new and "better" ways to kill, main or cripple our fellow man-- But back to brother Larter's original question--I once read a Jim Carmichael article about his boyhood years in NE TN-- where the Model 12's rules the roost- he mentioned a Fulton double in the house, but the American (Spencer- John Browning M 1893) gun designers and gun company top executives ( Bennett, Dodge, etc) were all cut from the same cloth as Morgan, Frick, Gary, Carnegie, Rockefeller- etc-- the post WBTS years- 1870-1910 were the greatest boom years for the Industrial Revolution-- and Winchester under Bennett proved that, by buying all the designs (except the A-5 shotgun) John Browning could crank out, even designs that would never see production prototypes- the profit margin on repeaters, especially pumpguns, was far greater than on the hand-fitted and filed double guns- thanks in part to Eli Whitney and the "go-no go" gauging and interchangeability of machined parts.
Jim Carmichael also made the point that as the Model 12's were the biggest seller, even into the Depression (when John Olin lowered the dealer retail list for a field grade M12 from $49.95 to $39.95- and most hunters, whether for the market, or to feed their families, were a one shotgun owner- they usually bought a 12 30" full choke- partly from the notion that as the retail was the same for a 28" or a 30" M12 so choked, you got 2" inches more of Winchester Proof Steel for the same dollar--
Also, from about 1920 through and into the post Korean War period, the Winchester Model 12 in Trap and Skeet editions ruled the roost on the clays tournaments- why? because guys broke great consistent scores with them, and the Model 12 would hold up to thousands of rounds of serious shooting and never break down--
Americans are both practical, and now with the revival of SC, the usage of special non-toxic loads for migratory birds being the "law of the land" also sentimental- and that's possibly why the renascent interest in the vintage quality American double guns--