I don't think traditional muzzleloading will ever die. Sure, it might not be fashionable right now, but when a lot of the current members got into it, we had Jeremiah Johnson on the silver screen, etc. That got a lot of guys started, true, but the sport still had appeal.
I'm only 22 myself, and skipped over inlines entirely, had a caplock for a while then went to a flinter soon after. I'm thoroughly hooked. Flinters have a certain magic that you just can't get with a suppository rifle or an inline.
I imagine that as the years roll on, muzzleloading will wax and wane with the times, but it will always be there, lurking, waiting for a big blockbuster movie or a change in hunting regulations. Heck, look at SASS. How many folks do you think were out shooting their single action pistols and coach and lever guns for fun before SASS came along?