That's an assumption.

I have never owned a NIB game, but I do know that every other game I've owned so far shows (at least light) playfield damage around posts, bolts, screws. Even in areas where the ball does not come, eg. a post which is not directly hit by a ball there's always slight lacquer/paint/imprint damage wherever something is bolted to the playfield.

Pinball machines are meant to be played. You're mashing a heavy ball bearing around a wooden playfield populated with plastics, posts etc. which will damage over time. When a pinball gets its intended use (which is hundreds/thousands of plays), a 1mm pooling circle which requires a magnifying glass to be seen will be the least of your worries in terms of wear & tear. For this reason I can understand that manufacturers do not have fixing of sporadic pooling damage during production on the top of their priority list.