Traditional muzzle loaders are dying because of themselves.
I am 48, been shooting sidelocks since 1988 and am always the youngest guy shooting them, no matter where I have lived.
To get the young guys in, you have to peak their interest. The rage now is the tacticool manure. But, lots of them are slowly seeing the ways of a good bolt gun. ML's can be the same way.
Bashing someone cause they shoot a modern ML, or adjustable sights on a sidelock, or dont use rendered bear fat for lube is no way to get them pumped about this hobby.
If someone wants to start with a modern ML, let 'em, hell, encourage them. Get them interested in a modern front stuffer, then introduce them to a more traditional gun.
Nothing turns me off more than some "traditional" guy, giving me a hard time because I have adjustable sights or dont use a spit patch. Caught hell because I had a custom barrel built and put a peep sight on the gun, because I wanted a 100 yard target gun.
I dont want modern ML's discussed here and not saying we should, but dont turn your nose up at some young guy with a modern ML. Get them excited about pouring powder down a barrel, them start taking them back in time.
All I shoot is holy black and PRB's. I dont care for the modern ML's. But, the enemy is us.