Are SONY the first gaming company to have 4 systems on the go at the same time?

[PSwii60]

The only other one is Nintendo:
Market availability until discontinued by Nintendo:

Japan:
NES (7/15/1983-2003),
SNES (11/21/1990-Sept 2003),
N64 (06/23/1996-2003),
Gamecube (09/14/2001-02/22/2007)
Gameboy Advance (09/21/2001 through 2008, All series)

So, Japan has NES, SNES, N64 and Gameboy Advance series for years 2001-2003

North America, twice:
NES (10/18/1985-1995
SNES (08/23/1991-1999)
Virtual Boy (08/14/1995-03/02/1996
N64 (08/14/1995-03/02/1996

So North America has at least NES, SNES, Virtual Boy and N64 for the year 1995

And,
Gamecube (11/18/2001-02/22/2007)
Gameboy Advance (09/21/2001 through 2008, All series)
DS (11/21/2004-2007 All Series)
Wii (11/19/2006 - Present)

so, North America has Gamecube, Gameboy Advance series, DS and Wii for years 2006-2007

Remember, I only included up to the time Nintendo supported the system. Japan's NES support can obviously be argued (supported through 2003?) as is the DS line (discontinued, apparently in 2007)
Source: Wikipedia.org; Take it how you will :)