Nah, not when NEC of all people eventually released the last game.
To me, personally, a system is dead when the last officially licensed piece of software is released. The Neo finally died with...SamSho5 Special (or whatever it was), the PCE died with Dead of the Brain, the Dreamcast seems to have died with Under Defeat, but you can never be certain when a game is in fact "the last game" (see: the last 10 DC releases).
Of course this theory gets a bit hazy when you consider machines that weren't %100 dependent on official releases in this first place. Is the MSX dead? The 2600? The NES certainly is. Very fuzzy.