Why manufacture objects in 10 different colours if you know the green one is going to be a tough sell? Why buy a blue car if you think you’re going to sell it back after 2 years and struggle to do so?
You don’t want things you don’t intend to keep to have personally, period.
Like it's a perceptual disease where there's a difference between real preferences and perceived preferences and people are making decisions based on their wrong assumptions about everyone else, and when everyone is doing it it becomes true even though we're collectively all making less optimal choices.
When we bought our current house it was perfect except the colors were an awful neutral grey - I had a hard time convincing my wife despite the otherwise perfection, and only did because we spent several thousand dollars getting it repainted before we moved in. I'm sure the sellers realtor thought the neutral colors were a great idea, but they almost cost several thousand dollars (there was a bidding war when we bought the house, we almost didn't bid and so the sellers would have lost).
The important point is if you like color make sure you pay for it, and reject things if they don't have the color you want.
No, but they certainly can be "buy it for the life of the car". I prefer that myself. New cars are nice, but I'm not going to trade up to a new car every few years. I will buy new (or new-ish), and then drive it until it dies 15 years later. Much more cost effective.
You can get a black one, a white one, a grey one, or then maybe two or three others that are most often in a red/green/blue/green which is really more of a flavored grey or black. Currently the Toyota Camry, really the only paint you can get where I'd (in a perhaps slightly silly restrictive way) would call "a color" is red. The other 11 options are either greyscale or slightly tinted greyscale.