This is all general information. Duke3D's Build engine was based off of the DOOM Engine, not the Wolf engine. There's no way in HELL the Wolf engine could support all of the advances Duke3D had, the technology was leaps ahead. Hell, Wolf3D couldn't even render floor textures and the walls were pseudo-3D. In any case, 3D Realms didn't steal the engine.
Congrats on making a thread based on a complete lack of accurate information, internet detective.