Back in high school, if you wanted to paint a car you stripped it with aircraft remover, wiped it down with acetone, then dragged it into the spray booth at the auto shop and shot it with PPG. If you mixed it right, it didn't even orange peel. My buddy, when he sold his landcruiser, put a $800 paint job on it that looked fucking spectacular.
He's doing a frame-off media-blast resto on an FJ40 right now and what we've discovered is you can't get paint done. If it isn't an insurance job, they don't want to touch it. The places that will charge in excess of $8k. Yeah, there's Earl Scheib, but c'mon.
It isn't about the paint. It's about the environmental regs for spraying them, and those are the exact same for iridescent silver as they are for bright red.
Psychologically, the more color you commit to the more mentally at ease you feel. Staid, conservative blacks and grays are all about discomfort; garish shades are all about peace of mind. Cars - at least the cars listed in this article; my wife's 2009 Honda is a bright f'ing blue - for the middle-of-the-road consumer are in grays, whites and blacks for the exact same reason there are a lot of shows about fairy tales on the air right now: people are unsettled.