No. Prices can go down however that doesn't mean we are back to "square one". Square one was genesis block and almost nobody mining, nobody knowing about Bitcoin, no where to buy or sell them.
If Satoshi were to dump 1M BTC on the market overnight that would be stupid. Why do you think Satoshi is stupid? Still even if he did the price would go lower, other people would buy and in the long run Bitcoin would be stronger. 1M BTC now in the hands of thousands of more users.
As far as I could tell, nobody here knows satoshi in real life. So it's relying on judgement only for thinking if satoshi was stupid or not. How do we know he didn't start bitcoins as a hit and run operation? 5 years, and now he's a multi-millionare. Not bad, eh?
Look, I'm not saying that this is true. I don't beleive it is. But I just wanted to bring this idea up, to see what others have to say.