I don't think that anyone is claiming that every Tom, Dick, and Shorty carried spare cylinders for their revolvers.
To say money was scarce doesn't, however, mean the same thing as "no hard money was available and never had been so no one could afford to buy, sell, own, or possess anything."
I've always taken a pretty dim view of expressing any historical touchpoint in absolute terms.
It's also odd that you'd dismiss as historically inaccurate the scene from Pale Rider while embracing as historical truth the scene from Open Range.
Odd, but then perhaps that explains the fascination some have with zombie movies...
But, in any event, at least one period gun appears to have been offered for sale with not only a spare cylinder, but also a spare barrel.