Brass availability is really what drives the "will it or won't it" survive thing, long-term. It's why I'm bumming on 7 WSM; Winchester hasn't made more, and nobody else picked it up.
I think what really drives survival are not the loonies like us on here, but the run of the mill factory load/factory rifle shooters who buy factory ammo and factory rifles up the whazoo.
Really I don't think "we" drive too much of anything to the same extent that factory load shooters do as we are in the minority. If we did,brass would more available and not apportioned to factory ammo production.
That said I suspect the 300 WSM has earned a slot...after 4-5 of them I never fell in love but it certainly works
