For me it's not a lose. The best strategy is sell at the peak and buy at the dip. You never know what's coming so better to take advantage of the ups and downs. But this is only for people who has all day to monitor the price of bitcoin but if you are a long term holder then there's nothing wrong.
but i think yes we can consider it as a lost because we have missed a good opportunity of making money in a short time. i think whose people who even invest money in bitcoin when it was trading in 2300$ they are also now getting a good profit form it. and if they will still hold it then there ar more chances that they will make their investment double in few months.