With access to the web, and the availability of steel data these days, it's a fairly easy thing for a knowledgeable knifemaker to acquire and use steels from anywhere in the world.
Generally if a specific steel isn't being used by a number of makers, it's likely because that/those steels have less to offer in a blade than what the maker(s) is currently using. There are a number of makers who have, and do use rwl34....very similar to ATS34. I personally have never used AUS8, but have tested a number of blades produced from it....there are a number of steels out there that make a better blade.