iskra said
A lot of interesting guns have fallen by the wayside according to their chamberings. Winchester, only one of many, “to big to fail” for sure. But no gun makers their cartridges.
If marketing a “new & improved” cartridge nowadays is ‘rocky’, consider over a century ago! Not just advertising, nor even getting products into the distribution chain to retailers. Cartridges themselves! Who, depending on their guns as our great grandfathers did, wished to be sitting without ammo! Buying such a ‘new & improved’ chambered gun then, a considerable challenge if located very far beyond ammo manufacturers/volume distributors & dealers. The latter who might at least be persuaded to carry the more ‘exotic’ chamberings for customers.
Owner situation with ammo exhausted and renewal likely up to a couple of months away in cycle from then snail-mail order to ammo sources possibly half continent away. Payment channels ‘hanging’ with such as money orders. Then the horse wagons likely at both delivery ends and perhaps with luck, rail in between! That contrasted to simply walking into the local general store and picking up a case of thirty-thirty or forty-five seventy. Winchester unquestionable reliability extending beyond whoop de-doo weapons, but apparently even then not beyond occasionally such ammo adventures. The most interesting rounds meaning little without reliable ammo supplies reaching customers…
My take
John  

John – I enjoyed your thoughts. I had not fully thought through the cartridge availability issue.  I wonder how common it was back then to figure that when you needed a box of ammunition, the local store would have to order it for you.  Reminds me of the movie, “Oh Brother Where Art Thou” when they could have what you needed,  “in about two weeks.”  If you think of that time period – and the big overlap of black powder and smokeless cartridges – it would be overwhelming for a store to have that kind of inventory.  I’m thinking of just covering the .38 and .40 caliber chamberings in two Winchesters – the model 1886 and 1895, you would need to have .38/56, .38/70, .38/72, .40/65, .40/70, .40/82, .40/72 and .405.  And then, there were options (bullet weight, style – such as jacketed or lead, powder type and charge).  It makes sense that plenty of shooters had a bead on what their local stores usually had on hand, and that influenced their rifle selection.