I believe that vast numbers of Bitcoins were found and lost in the early days, because back then, people were mining just because Bitcoin was an interesting technology project. When they lost interest and quit mining, wallets were easily lost in OS reinstalls etc. because why would you bother backing up a bunch of funnymoney?
So I predict that a big portion of those early Bitcoins that have not been moved, will never ever be moved, because the wallets are just lost.
I tend to disagree. Who reinstall their OS without migrating his data? Also: the early early miners where probably "hoping like hell" it would succeed, why else go to the length of writing the code. A backup of wallet.dat is cheap enough. I don't think many of the old coins are lost, but that's speculation for now.
EDIT: also, I see what you did there. Your prediction might be very hard to falsify.