It’s going to take a lot of dirt to bury the .270 Winchester. The .270 has enough “wallop” to kill anything in North America out past where most people should be shooting.
Rifle manufacturers could easily be making faster twist barrels to shoot heavy for caliber bullets in the .270, but they work in conjunction with bullet manufacturers to sell new rifles and cartridges. These become a package deal to get people to stop using what they already own. As you noted, the 6.5 PRC and .270 Winchester are very similar within normal maximum hunting ranges. The difference is purely marketing.
I just had my old custom Mauser .270 cut (21”) and threaded so that I feel comfortable continuing to use it for years to come. Wearing her OG she measures 46.5” long and 9.9#. I will probably upgrade the old Redfield scope she wears (and the mounts, which I don’t consider a reliable design), but she’s been a great rifle for me for over 30 years and I expect she will only get better with age.
____________________
“Keep on keepin’ on…”