I'm sure the donator ranking was created when Bitcoin was worth a lot less than it is now. 10 Bitcoins is a lot. I wish I had enough to donate.
I think that must have been when 10 bitcoin was no big deal, because at the rate it is now, I don't see any member willingly parting with that much. I think a review is highly necessary to reflect the present state of things. Would be good to know if any member have actually made this donation till this moment.
They did make it back when BTC wasnt big. however they likely see no reason to change it. they probably have more then enough and the current donators will likely be upset if they lower it because they paid that high of an amount.