You did, until Golden Eye N64.
And many of those early games (Wolf3d, Doom, Hexen) didn't have Mouse look on be default, you played them Closed (Arrow Keys and Right Ctrl/Alt) or Open (Arrow Keys and Left Ctrl/Alt).
It really wasn't until Quake I/QuakeWorld that FPS' made the shift to Mouse+WASD. And evenstill in Quake1, mouse look was off by default.