The 485-489 range was a very long time before it was confirmed, actually it was confirmed, then changed to a snr range, then reconfirmed as a sheet replacement.
so other than brick searchers, none would likely have been saved in any circulated condition.
as far as their not being many in uncircualted condition, either they are on hold by collectors, assuming they will be worth more due to the previous reason given (I sold my AOS4850416 on e-bay 5 or 6 months ago, and if I remeber correctly I believe I got over $100). Any other reason only the BofC could answer.
just my 2 cents.