There’s not a lot of margin in making ML parts. Machinists can make more money doing other things. I can’t imagine the work in buying round stock, deep hole drilling, reaming, rifling, cutting breech threads, making and fitting a breechplug, and then precisely profiling the barrel, all to sell it for $300 while using $50,000 worth of equipment. Same with foundry work like lock castings. There has to be a passion for the work that surpasses reason.
Outside of muzzleloaders there’s no other gun thing like it. Yes a few outfits build custom modern guns but it’s nothing like the numbers in our hobby. And it’s hard to explain to the non-enthusiast why a pile of parts requiring a hundred hours to make into a finished custom gun should cost $1000, when they can buy a modern gun all ready to go for half that.
Get what parts you can, now.