IMO I think it will die not because of the users, but probably if the miners forfeit mining.
You realize that mining difficulty will adjust downwards if many miners stopped mining, resulting in the remaining miners starting to profit again.
Even when there are no more block rewards there will always be mining as long as users keep making transactions with non-zero transaction fees.
So far, after the halving, there is no noticeable difficulty drop. It means the S9 is replacing old miners.