I'm guessing time constraints had a lot to do with it. I believe there was even an unused schematic for the Rock-It Launcher that they forgot to remove.
I could see this for *new* weapons, but the already *done and in the geck* ones? Unless some miscommunication occured, something along the lines of:
"OK, thanks for coming to the progress meeting, folks. Now just an update on the craftable weapons. I've got all the meshes, textures and scripts done for the weapons, so we're ready to put them in the build and test 'em. Now you area designers got plenty of the required parts scattered in your world spaces, right? What? Whadda mean? You NEVER GOT THE MEMO?"
The possible reasons fall into these catagories:
1. Design decision to not have them.
2. Intended to have them, but had problems with implementing them mechanically (engine).
3. Intended to have them, but had problems with implementing them organically (someone screwed the pooch).
4. Intended to have them, but had problems with implementing them chronologically (time).
-Gunny out.