And what's more, stamps are not essential to daily life, and sooner or later you'll have to get all those accumulated stamps off your hands, and at that time supply and demand will change places, so the price will "go straight down."
何況郵票不是民生必需品，屯積一包包的郵票遲早要脫手，到時候轉需求為供給，價格就會「直直落」了。