If you will look to the bitcoin's lost value and total bitcoins circulating you can say that it will not drop, if there are 21 millions of bitcoin around the world and the 80% has been mined then only 20% will needed to be mined but on that 80% its not literally circulating almost half of it are hold by the whales. I think bitcoin's value will increase as its limited number is slowly reachable.
That is is if people are holding bitcoin and they are not going to sell their bitcoins then its value value will be increasing because of the increasing demand and low supply. With the passage of time the demand of bitcoin will continue increasing because of the people still taking interest in bitcoin.