I doubt it, at least not for awhile.
The JRH is really an enthusiasts cartridge and unfortunately enthusiasts don't make up the vast majority of shooters.

Add to the fact that the majority of people's recoil tolerance seems to drop off right in around mid range 44mag loads I think the 500JRH will remain a handloader's and enthusiasts cartridge.

One other thing that hinders it is the lack of commercial brass. Yes you can cut down 500 S&W brass and that is how I made mine, but many don't want to go through that process and with Buffalo Bore having the only stock of factory 500JRH cases at $1.00+/case it makes it a hard sell for many.

***I have wondered if Buffalo Bore has some sort of exclusivity agreement with Starline on 500 JRH brass. They were early on the bandwagon and ordered enough brass for Starline to make a correctly headstamped run for them. I would bet they pushed for some form of exclusive agreement to ensure that they would be sole supplier until they decided not to any longer or they were able to sell all of their existing 500 JRH stock.