I think you are wrong. Bitcoin supply isn't all 6M bitcoins that have been minted, but only those that are used for trading. From the market point of view, bitcoins that have been minted but never used for trade, might as well not exist. I suspect that a lot of that kind of coins are entering the market for the first time.
What coins do you expect have the highest probability of entering the market? Coins bought by "hoarders", or coins "minted" my miners? Putting aside day traders and the like, several elements indicate that a miners is much more prone to sell his production than a long term investor is.
Nevertheless, the point stands. A coin that has been accessed through trading, no matter how long it is held upon, has already brought in dollars in the market. A freshly minted coin didn't.