I think part of the huge popularity of traditional muzzleloaders years ago was due to the implementation of special muzzleloading only hunting seasons. For example, here in NY, muzzleloading season originally mandated the use of patched round balls only, and no optics. I, myself, originally bought into this sport due to the expanded hunting season. Human nature being what it is, people/manufacturers started trying to improve/modernize/simplify the process of using a muzzleloader. Hence, the polypatch, substitute powders, rifle primer adapters, speed loaders, and so forth. I think the shift to the "modern" muzzleloader was a natural evolution of this process. Just making it appear easier for the person who is not a true muzzleloading enthuiast, and just wants a longer or earlier hunting season with the least amount of effort as possible. This natural progression of so-called "progress" led to the changes in hunting restrictions. NYS eventually changed the law to allow elongated projectiles and optics in muzzleloading season. So, in the end we have the majority of consumers (who by and large are not traditional muzzleloading enthusiasts) dictating the demand for non-traditional products.
As an aside, I currently know of no other hunter in my area that used a traditional muzzleloader. When they see what I am using (one of my T/C Renegades), they are quite puzzled as to why I would use this type of firearm.
Likewise, there has been pressure on our state's DEC to allow crossbows in archery season. I bet that a good many compound bow users will embrace the crossbow if the law is changed. I am not being judgemental on this issue, I just think it is human nature.
Larry