Not sure where I heard that one first but anything that's made to be a collectible cannot have long term value.

If things are sold as "collectibles" that means the market will be flooded and people will treat them as such, i.e. there'll be tons of mint condition items around forever.

The only collectibles that appreciate in value (at least beyond the short-lived marketing hype) are things that never were meant to be collectibles, e.g. stamps, baseball cards, coins, comics, etc from before they became collectibles.