Adam ...
There is no question about the popularity of the inline over the traditional offerings, and I'd be completely surprised if traditional offerings today even met the 5% volume in new sales overall from year to year.
But, from an ownership standpoint, I think I would agree that many of us that own inlines also own flintlocks, caplocks, underhammers and the like. Many of us also own replica civil war muskets, just because, and I'm certain that that number probably does exceed that 5% number by some larger margin.
Aloha..