Over half a billion dollars a year...
Sammy's pachinko/slot amusement business brings in all of this profit, yet it takes little investment from them and leaves them with nothing to spend their money on. They chose SEGA to help them expand across the video game field in a big way, with big funding in tow. Third-party publishing for consoles isn't a successful business for SEGA, though, so Sammy might be looking toward hardware instead with the company's combined experience in the field. And, of course, SEGA much prefers to lead the way on a first-party platform, too.
Sega Sammy still have the right contacts for system design work. After seeing how well their last console faired technologically against newer competition and how well the 2003 MBX still compares to other entrants today, it'd be exciting to see what PowerVR could do in a new console. Solutions from Renesas would be interesting to see, as well, since it's been a long time coming from the SuperH division they now control.
2009-2010 is a possible window of opportunity.