I don't know the round counts used at certain points where he describes problems. He often - in stages, to avoid overheating and while checking headspace - reaches 3,500 rounds in many of his guns.
With low grades of commercial steel he has seen premature wear on lugs, shoulders, even carrier tails. It depends of course on which brand he tests.
Riley Defense AK47 - Broken Hope... - YouTube This was several years ago

. This is linked in case anybody is interested.
https://www.youtube.com/
For what it might be worth, only a few years ago he tested a (then) new WASR up to 5,000 rounds with very good results.
No premature lug, shoulder, carrier 'tail' wear nor any headspace issues.
It really pays to first spend hours reading about a new gun type- and only from "non-commer$ial" reviewers.
I never buy a gun simply because it is attractive and "US-made". Appearances mean nothing but are seductive- the Lorelei's enchanting song as you drift toward the rocks.
Rob's huge viewership and problems with the AKM produced by Interordnance was a major factor leading to IO's Shutting Down of their AKM production.