Let's do this by the numbers:
Wolfenstein 3D - Source provided. Why port an old game no longer making sales?
Heretic, Hexen - Raven did these (like the new Wolfenstein...) but they did the same thing with Wolfenstein 3D much for the same reasons.
Rescue Rover, Hovertank, Catacombs, Dangerous Dave - Same story as Keen... Nobody but DOS PC's have a version of this.
Quake 4 - Jointly Developed between iD and Raven. Since iD had an involvement, TTimo was involved to do a port there.
In short, you had a small point about the old DOS titles, but your info on the others is off. Wrong. That's the point I'm trying to make on all of this.