My Swedish Mauser was issued in 1903. It was decommissioned & surplused in about 1932 (when it got german civilian proofing) with barrel wear beyond acceptable for continued army use. According to the plaque. It's still got it's original firing pin, ejector, extractor etc. and the bolt doesn't fall out by itself. The barrel however has more erosion than the Grand Canyon. And the firing pin hole looks like, well, an asshole. Since 2020, when I got it, it put 800 rounds through it. On a day with good light I can hold the black on a ISSF 100m target. The rifle is still capable. It's far from a sub-MOA rifle. But it's still good. The limiting factor are my eyes & the tiny sights. And the only thing worth replacing - would be the barrel. Everything else, probably good for another couple of 10.000s of rounds. Man, I'd love to know the count on it!!
If modern rifles use even better material - well, that's just awesome! In that case I'd assume a modern action will never ever wear out. Unless you go full Kentucky Ballistic on it.