Why Max Prestige?

I've always wondered why in the COD games they never add extra levels of Prestige.  How hard could that be?  All they'd have to do is load one extra symbol for all 50-60 levels you have to go to be eligible for the Prestige.  This has never affected me of course.  I rarely manage to get to a 3rd Prestige (trying to get to the 3rd on Black Ops), but still...why can't they add extra levels in updates?  It would suck to get the the last level and not be able to go any higher.  Then again, I'm a sucker for games that let you level up infinitely.  I'm lookin' at YOU Disgaea.