In Black Ops 2, the maximum number of times you could prestige were 10. Your solider maxed out on with the 10th prestige is the ultimate accolade in Call of Duty. Apparently, that's not enough.
A few players were able to bypass that limit and go to prestige 12. Treyarch has done nothing in light of the situation. Now, it was rumored a while ago that during an update for Elite, someone was able to find 15 images labeled "Prestige ". Later, it turned out that the additional images were from the original Black Ops.
There was 15 of them, so maybe the games does support 15 levels but the older images were there just for the time being, to be replaced later. I mean why not increase the level cap? If Activision wants to completely drain as much as they could from their players, why not raise the cap once in a while? They do that with Blizzard. Doesn't sound too farfetched to me.