You do you, and I and others will continue to advocate guys shoot cartridges that they can shoot well, because of reduced recoil. Between the 3 different threads we provided for the OPs research, my guess is the fellas consistently killing big game with "non-traditional" cartridges have killed more than 100 combined and congratulations on your success. Form has probably killed more than 100 big game animals with "small calibers" himself.
Regarding the 300 win mag, it is an excellent and proven cartridge no doubt. The recoil it delivers is also punishing and more than many people can comforably shoot. Moreover, compare it to a modern fast twist .25-06 and its a dead heat with the .25 pulling away at extreme distance. The 133 and 135 grain Bergers are "hunting" bullets and achieve very similar ballistics to the 134 ELDM if you don't like "match" bullets for hunting.
Look at the table and let me know what advantage the 300 win mag has over the heavy .257 inside 600 yards. The major negative it has at all ranges is about double the recoil.
Regarding the 6.5 PRC, it is also a good big game caliber. However, a very seasoned western hunter and guide that I know shot a big bull 7 times with one last year to finally put it down. The point being a marginally larger "caliber" does not in any way guarantee a bang flop on a deer or elk.