As far as the hardware goes, FN is one of the largest weapons manufacturers in the world and is certainly not going anywhere, not while they're still winning U.S. service weapon contracts right and left.
As far as the ammunition goes, FN isn't the only one making it, though Elite Ammunition is pricey. I don't know if Starline or anyone else is making brass for it, or if anyone other than EA is making non-FN ammunition. That's a bit of a hairy situation for someone who doesn't load their own.