I think if these extra long barrels offered any real improvement to performance that all makers would have pushed them as the latest and greatest. But they didn't and 30" to 32" seems to have been accepted as long enough. But someone who understood human psychology tried to make guns for a very small niche market. A lot of cheap single shots and bolt action guns in this country were offered in this country because "they just shot farther". Passing fads IMO.

When an old man dies a library burns to the ground. (Old African proverb)