If bitcoin happens to reach $600,000 , I know say many person go rush sell there bitcoin. But e get people wey go sell all there coins without looking back morespecially those that have been holding for more than 10yrs and whales .
Everyone has his/her goal , i respect that ! If they did sell at that time, it’s their profit so far they are good with it . However, I think most people would have realise it’s potential and will still love to hold even more and more at that price.. For the whales, I don't think so either .. I'm not them but I think most will just continue to shave little off from time to time while they still hold and if the opportunity to buy cheaper shows up they will still buy to make more 
it's just an investment strategy.