You could, but the renderer in unity is optimized to deal with environments far more complex than were possible in wolfenstein or even doom and thus uses very different techniques to put geometry onto the screen.

A psuedo 3d wolfenstein clone written with a reasonably optimized raycaster would probably outperform a unity version quite significantly. I don't know how well suited unity is for having 3d game entities represented by flat textures instead of 3d models for example.