You don't only need early adopters for such statement, you need early adopters who cared at all about they wallets through all of this time. Some people might have mine a lot of bitcoins in 2009 for fun and forget about them .
I guarantee this is the case. While 21 million will be mined, I'm sure a lot of those early coins are gone due to loss of the private key. How much we'll never know but I think it's more than people realize.
This happened to me with name coin (which, btw, is an awesome idea and complement to bitcoin). I had a miner doing name coin for the web value, and at some point I stopped mining. I kind of forgot all about it. Fast forward where I realized name coin was trading over a dollar (I forget what it is now, like 2 and half or something?) and I realize "oh shit I never backed up my name coin folder". 500 name coins gone, *poof* vanished. Oh there're out there I s'pose, out there in the nether, but it's 500 i'll never be able to use *sigh*
