There are persons that may have been unlucky with the timing, but I have found that most people that miss the timing are those that do day trading, those that buy and sell their bitcoins on a daily basis, those that just buy and hold for months are able to ride the wave and to have profits.
to me i think no one can be perfect, i think every one must have missed the right time to buy or sell. i my self missed the right time for so many times, but still i am happy with my decisions as i have made so many bitcoins from trading while buying and selling on right time.
Trading can't really be perfect and that's what it makes difficult and you are right all of traders do experience to miss the right time to get in and get out because prices are really unpredictable on trading.even though we missed sometimes atleast we could able to handle it.