No one could possibly have achieved 2500 PvP wins yet. There have been 456 days since release. Assuming a player completed and won five battles every day, he would only have 2280 as of today. They should change the reward for this achievement, more than any other. It means loyalty. Whether you are a whale or not, it is going to take a minimum of 500 days to complete this challenge. It would certainly help with customer appreciation to give a vault of crystals to the players who have been most loyal. They should also do something special for the first players to reach this achievement.
Edit:
I don't think this would hurt revenue. Clearly these players aren't going anywhere, and most of them have probably spent money in the two years it took them to get 2500 wins.