Many games already have an option of playing them without vr.
But for the cases that don't it probably just isn't worth the trouble, you would have to trick your system and rebind all controls to move around XYZ positions for both hands and more axis of your body with keys instead, imagine having each button out of your keyboard to move each axis of your body it would be an worse experience than games like "hand simulator".
The hassle is just not worthwhile unless the game is already set to also work in non-vr mode.