Selling fast is of no significance if Sony can't restock fast enough to take advantage of the surge in sales. It does however send a warning to MS and Nintendo.
Not true at all. Let's just say the PS4 sold 1.5M in the days before and the day of BF, but don't have stock for the rest of the week. Then, the XBO has enough stock to ride out the whole weekend, but sells 1.1M. Who wins? It isn't the one who stayed in stock.
Besides, stores will have stock for actual BF. And I'm sure online retailers will have a few set aside for Cyber Monday.