Each cartridge has it's place. one is no better than the other if used under the right circumstance.
A 338 would not be usable for squirrel hunting just like a 22 Long rifle would not be recommended for elk. the 338 is at home and in it's element hunting elk size game at distances beyond the range of many smaller cartridges. the problem with bigger cartridges/diameter bullets, is that most people cant take advantage of the extra range while hunting. so they are not used to there limit.
No matter how good the BC"s are or how much downrange energy a cartridge has, you still have to place the shot where it counts. If you are shooting at steel then it doesn't matter what cartridge you are using as long as you ring the steel.
In my opinion, there are no obsolete cartridges. Just the ones that are used improperly and to much is expected of them. To much emphasis is placed on BC's and velocity instead of performance for the intended and proper use. Shot placement and shooter skill is still the most important thing in my opinion, and the proper choice of weapons for the intended use.
Tell someone that their favorite rifle/cartridge is obsolete, and they will tell you how wrong you are because they have had nothing but success with it.
J E CUSTOM