> If those coins are still held by some individual and they decide to unload the BTC will drop like a stone.
That would be the concern yes. So they won't make a couple of billions, but they'll make a lot, and the rest of us will be left holding worthless bits.
I'm sure you can see why that could make someone reluctant to buy into the system, since it sounds plausible, and we don't know for sure the creators are not in fact holding a ton of bitcoins.