CraigC has the right idea.
Contact Jack Huntington at JRH advanced Gunsmithing. 530-268-6877.
Find a field grade .454 for 1000 bucks, convert it to .500JRH, and, you'll have a custom Freedom Arms for 1000 bucks less then the .500WE.
Brass will be cheaper, and, last time I checked factory ammo was 33 dollars for 50. Heck, you can't find factory brass for that.
Do your homework. The .500WE runs at high pressure, more like the .500S&W.
The .500 Linebaugh considerably less.
Out of the .500 Linebaugh, really should have been called the .510 Linebaugh,
you can shoot Gary Reeder's .510GNR, or whatever he calls it, which is a really short .510 Linebaugh case, with the bullet sticking out the nose, but, it's cheap from Andy Rowe, and, comes in a variety of loads, from mild to wild.
Something like about a dollar a round, or a bit more.
Would help a bit for details to know what you are going to shoot, what temperature the area is, and if you reload.
My pick for cartridges go something like this:
.500JRH and .475 Linebaugh for the economical answer.
.510 Linebaugh, and .510 Linebaugh Max, only because I found a
.510 Linebaugh Max at a price I couldn't pass up, and, like the
ability to shoot .510GNR, .510 Linebaugh, and .510 Linebaugh Maximum.
.500WE is tits on a bull. The REAL cartridge was the .500JRH. Instead of giving the guy credit who designed it, and fit it into his revolvers, Baker
put a belt on it, and called it the .500WE.
As for your original question:
Freedom Arms is likely to be around. Don't see much sense in having a knockoff cartridge like the .500@e when the original is just a cut down 500 S&W and, does the same thing the .500WE will, for half the price, and, with
no question that the .500 S&W parent case will be around, and, that dies, bullets etc. are going to be far cheaper then the .500WE.
If you want to shoot 500 grain or heavier bullets, the .510 Linebaugh does that better then the .500JRH or the .500WE. They, like the .475 Linebaugh, top out at around 420-440 grains.
Looks like the WE loading data has been brought down a bit:
http://www.freedomarms.com/500weda.pdf
49k for max loads isn't low pressure, but, keep in mind, the above is pretty much identical for the .500JRH, and, the .475 Linebaugh.