low power is critical: most Consoles will sit in a poorly ventilated area, often behind glass.
low cost s also critical. There is a maximum price users will pay for a console, and if the parts inside are more expensive than that, you lose money on each sale. That happened with the PS3, it didn't break even on cost for 2 years.
the PS4 and XBone opened at $400, whicvh was about the value of the parts inside