Who wouldn’t want their car’s paint to look perfect, or as close to it as possible? It’s certainly not difficult to acheive in most cases…but there’s an important cost (and no, it’s not just the actual cost of the paint correction work).
Unlike custom repaint jobs on show/collector cars — which have as many layers of clear coat as the owner’s budget allows — typical car manufacturer paintwork has a VERY thin clear coat layer by comparison. Cost control is the primary reason for this, both in extra materials and the time it adds to the production of a vehicle.
The reason clear coat is so important is because of the protection it provides the colour layer underneath, both from environmental contamination and the sun’s harmful UV rays. In other words, take that clear coat away or seriously compromise it, and your car’s paint will start to degrade real quick.
And this is why paint perfection is a dangerous game for the average car — meaning any car that actually gets driven. Any time that deeper scratches or surface imperfections are removed or “detailed out” of the paint surface — as opposed to more common lighter scratches and swirl marks — what’s actually happening is that a small amount of clear coat is being removed via compounding and polishing. This process levels-out defects and restores uniform light reflection which looks better to the human eye.
Once this clear coat is removed, the only way it’s coming back is if the car or panel is repainted. Furthermore, the paint’s UV protection goes away completely if too much clear coat is removed. The worst part about all this? The effects of removing too much clear coat are typically only visible months or years later, long after “perfection” has been achieved.

So there’s the double-edged sword regarding paint correction. Any detailer who tells you “Yeah, I can get your paint looking absolutely perfect” had better know what they’re working with…and preferably have a proper paint-depth meter to back them up.