What innovative things has Nintendo been doing besides the Wii?Of top of my head and I am sure there are plenty more.
- D-Pad (1982 on donkey kong)
- L-R buttons on SNES
- redefining handheld console as we know it today (gameboy)
- Analog stick on a joypad (N64 had it first)
- Rumble actuator on a joypad (N64 had it first)
- revitalization of game and game console market with NES
- Touch screen interface on handheld consoles with dual screen (before iphone)
- portable handheld console with 3D without glasses
- 'portable' 3d console (virtual boy)
- (re)defining 2d platformer genre as we know it today
- (re)defining 3d platformer genre as we know it today (N64 super mario)
- vast collection of super brands of games and characters
- Wii and that whole thing with motion controller
- Wii U with separate screen on a controller
.... many many more
So, what has Valve done exactly? They created a marketplace for games which has revitalized PC gaming (debatable on revitalized - more like set direction) and several popular games. Don't get me wrong, Valve is successful and likable company now (remember when everybody hated Steam?). They are just not in the same category with Nintendo as far as innovation goes, not technically nor creatively. Maybe some day they will be, but they are definitely not there yet.