"The system will be available for $399/€399/£349 in 32 countries by the end of the year, the company said. The date comes just days before the Black Friday post-Thanksgiving sales, but given the strong pre-order interest for the system already, the PS4 might be hard to find on store shelves in the days after it drops. Sony revealed that one million PS4 systems have already been pre-ordered worldwide. The company notably did not mention a release date or price point for the system's launch in its native Japan."
IMHO, SNE and MSFT will wait till one release the date first.
Both playing little game theory by making time (t) as a variable.
2nd company who release their launch date will release earlier than the first company.