I think it will be forever before 243,270,308,30-30, 30-06, 300 win mag, 7mm rem mag goes obsolete. They will have invented something besides conventional ammunition to hunt with before these go obsolete. They are all in the top ten most cartridges sold by ammo manufactureres each year. These rounds will always be cheaper than most any other centerfire cartridges for meduim game hunting. And will always be more readily available. 6.5 creedmoor has moved in there with them as well. It has just joined that group, not necessarily pushing one of them out. I could tell you many cartridges that won't join that group and one of the biggest reasons for those is the initial cost of a box of ammo for them, not that it makes a difference to me cause I hand load. If cartridges such a 26,28,30 nosler, 6.5 & 300 prc are to join that crowd they will have to get in the price range of $15-$25 a box on economy versions of ammo. I just don't see that happening.