It could happen when we are not taking an action now to invest we might not see a cheaper price again, but you should make sure you are willing to take the risk because we have witness the price has fall back many times so it should be an individuals decision as both could happen, but my stand is I will see another good price before the end of this year.
I think invest Bitcoin for fast term not give profitable for us, to get profit I recommend to buy and sell about 4 years again. In this year, I sure the Bitcoin price not reach $700, maybe between $ 500 - $650.
The longer we will stay with bitcoin the more we will get the profit, so it is better to buy bitcoins for our future as it is sure and confirmed that the price of bitcoin will increase and it will be an established currency in the future so we will earn much more with that.