Well, what you are saying is very true. Those who bought during December 2017 are seriously in deep lost. They have to hold for more years before they can regain some of their profit back.
Well if they are still holding but i bet there are only few of them who hold because if you will going to check the bitcoin market price it currently drop that fast in just a day you can see that everyone is selling out their bitcoins. And aside from that there could only be lesser percentage that when buy bitcoin that time you are still holding it right now because i do believe that they accept already their lost which means they trade already their bitcoins.