I've been an MMO gamer for a VERY long time and I would say the whaling thing is a perfect analogy. I often pre-order expansions to MMOs like WoW and FFXIV but I have never bought cosmetics other than two race changes for FF, which would make me a "dolphin".
I noticed in WoW and FFXIV that if someone has one mount you can only get from the cash shop, they are VERY likely to have bought TONS of other cosmetics from the cash shop. If they don't have any cash shop mounts, they won't have any cosmetics from it either. It seems like most people are either "all in" or nothing, people like me are very rare.