The real scary part is, if the miners do not sell their coins, technically speaking someone can have all the bitcoin in the world. Think about it, let's say you are a miner, you can pay the bills and the costs from your pocket, after the 21 million is over and there is no more new bitcoins, that means the only thing you are mining for is the fee's right?
Well, when you keep going for that fee, you are taking other people's money and not new bitcoins, if you do not sell them, eventually you can have ALL of them as well. Obviously it is not possible with the time table and how it would take longer than one life time to be able to do that, but I really dislike the fact that it is technically possible for something like that to happen, it should have been covered over with a protection for something like that.
This problem could be solved by creating an extremely small demurrage fee. The problem is that even if that demurrage fee is only 1 satochi per block (one satochi from each wallet go back to be mined each block), this become 0.0005256 bitcoins per year, a value that is not low enough.