I think what's being said, or at least what I am saying… is to buy something at retail price for no other reason than to re-sell it at a higher price isn't a great thing to do. To buy something because you want it, eventually loose interest in it and resell it to someone who wants it now at market value is a different thing entirely.
Also, "investing" in collectable items be it antiques, paintings, or action figures isn't really a great way to make money. The market is far too volatile and unpredictable and even when you do make good, you get much better returns on other sorts of investments.