#1 cause of barrel wear is over-cleaning, especially with hard brushes. Literally, all that's needed 99% of the time is a cloth swab wet and one on a jag to dry.
I used to run a thousand rounds a month in a rifle and a pistol, each, in competition and training, formally cleaned the guns once a year:
AR-15: lube bolt and BCG before match (hose down with CLP or whatever, shake dry, look for broken things), pick crud out of extractor once in a while. Round count is ~ 25,000, still shoots 1 MOA w a CMMG chrome-lined 1:7 barrel.
Pistol: Hose out with CLP if rolling around in sand or gravel. Cloth swab down barrel then too. Armalite AR-24 (Turkish-made, all forged steel Tanfoglio-pattern): ~ 60,000 rounds, Glock 19 Gen 3: ~ 50,000 rounds. Both have about 10 years of monthly 3-gun and monthly (or twice) IDPA matches on them, plus training, courses, etc. The Glock did a year of matches, training, and CCW duty for ~14 months with only external wipe-downs.
Remington 870: Whenever extraction would "stick" it was time to lube the locking block and grease the action bars. If the interior got wet, it would also need a hose-down with CLP to stop rust. Round count: No clue, 120 rounds once a month for 10+ years, plus hunting, clay shooting, and some bigger 3gun matches with 300rd+ over 2 days.
Let's say all of the internals of the above are "well polished" but they all remain within factory specs and are 100% reliable under both match and tactical training conditions, including a day's worth of inhaling gravel dust, although the BCG would get hosed down/out with CLP every couple of hours.
And to think how much I cleaned my service rifle