In the end, it's all supply and demand - even gold is no exception.

Sure stamps are collectible, and have some value, but at the end of the day it should be within reason. At the end of the day stamps are simply brightly coloured bits of paper, and their price should reflect that. Some of the more expensive stamps go for hundreds of thousands of dollars, even millions, which goes so far beyond what is reasonable that the only logical explanation is that the buyers are paying purely for status. Which makes them no different from NFT's.