Low mintage doesn't really mean anything. Its not the mintage that gives the coin its value its the demand. A low mintage certainly helps but all you need is the number of people who want one to out number how many there are. Think of it this way a coin could have a mintage of 10 but if only 1 person wants it theres no demand for it. Another could could have a mintage of 2 million but if 4 million people want it its price will shoot up from demand.
The other thing to consider is that for 9-11 there were A LOT of privately minted memorial medal/coins and frankly the vast majority if not all of them had a more meaningful design on them. There is a lot of private stuff out there this medal is competing with. Its not like 9-11 was some obscure event either, these medals were advertised on tv and people still stayed away from them.
The other thing about this is medal is it really cant be compared to other things that have been over looked in the past to be discovered at a later date because of what it represents. The 9-11 attacks had a dramatic effect on the country both at the time and its future direction, in fact we are still involved in actions from. I bring that up because its a very emotional issue for people. Some people cant look at the medal or talk about 9-11 without crying, others get very angry at the subject. The design on this medal really angered a lot of people (myself included) and theres some old threads on it here. I'm not bashing anyone that likes it by any means, its just that its something that you like or you dont. Due to the fact its for 9-11 whatever your initial impression of it is thats what your impression will be forever. You arent going to look back 5 10 years from now and say you know what I was wrong 9-11 wasnt that big of a deal and the medal is fine ill get it, its one of those events that sticks with you forever much like pearl harbor did or the jfk assassination for older generations.
With all that said I dont have a magic 8 ball that tells me everything that will go up or not so I could be wrong and it could happen. I just dont see personally why it would. If you like them though 40 dollars is a good price to pick up a 69