Sega has had a loss of a little over $500 million in 2007-2008 and has not had much success.Maybe its time for a Dreamcast 2? But Sega has never been the same every since Sony's release of the Play Station 2 (Japan March 4, 2000 - North America October 26, 2000).
The Sega Dreamcast could not compete with the Ps2. The Ps2 quickly decreased the sales of the Dreamcast not even 2 years after the launch of the Dreamcast. The Ps2 had a DVD player and their game disc were DVD-rom and had much more space. The Dreamcast had online capabilities but they were soon blew away by Microsoft's Xbox that had introduced Xbox LIVE which was a much better experience because it had The Halo franchise and the Tramcar only had Phantasy Star universe.
If Sega were to make a new console some things they would need to look into are...