Probably he means the gun was shot so much that the barrel lower and upper lugs developed enough play to be noticeable in accuracy. I imagine the slide to frame fit could also loosen, but its effect on accuracy is not very drastic.
A barrel might lose its best accuracy through wear of the bore, but that should take tens or even hundreds of thousands of rounds in a 45 ACP. A powerful Open gun in 38 Super or similar high velocity caliber could lose its accuracy a lot sooner, just like a rifle.
I have a few 45 ACPs, too, but they do not move in packs so the photos are one or two at a time.
The S&Ws first.
SW1911PD
SW4506
SW945PC
A couple of aluminum Kimbers, Tactical Custom II and Tactical Pro II
Les Baer Premier II
STI Ranger II
I do not have enough 45 ACPs as you can see, so I am already planning how to improve the situation.
45 ACP is such an enjoyable cartridge. It has historical character. It makes a full, fruity sound when it goes off, the recoil is a nice soft push. It leaves an easily visible hole in the target, which is sometimes useful in a hectic action match. The cartridge is very easy and forgiving to reload. And by reloading you get 45 ACP ammo at the cost of factory 9 mm.
Negatives? There are so many excellent 45 ACP guns on the market you can go crazy trying to decide which ones you can afford to own.