I think you said the most important word . . "affordable". A lot of folks haven't got a lot of spare cash these days. The italian revolvers allow them to get in to the hobby cheaply - I say this in comparison to what a good vintage Colt or S & W cartridge gun costs . . . plus, they use them new fangled cartridges. If a person looks hard enough, they'll come up with an Italian repro. that is used and priced even more reasonably than new price at Cabelas and such . . .
And, as mentioned, the "historical" aspect plays a big part of it as well. If I was strictly a target shooter (a serious one), then I'd consider a Ruger if they were still in production - which they aren't. However, I also love the historical aspect of the repros as well . . no, they might not be 100% in duplication, but they are the closest you're gonna get for one that's a shooter . . .
I would certainly buy "American" IF there was a company producing a historically accurate model that was high quality at a reasonable price. I have a number of moder cartridge handguns, Colt, Ruger, S & W (most of them "vintage") and I only have one that is foreign made.