Minor nitpick, but Carmack didn't create the tools for id's games. Romero made most of the early tools until his depature.
BTW Carmack released the source code for QuakeEd back in the mid90s [1], however it was written against the "traditional" NextStep APIs which were incompatible with OpenStep or GNUstep and AFAIK nobody ever ported it to anything nor managed to compile it.
EDIT: also id did release an editor before QERadiant - in fact this is how QERadiant came to exist :-P. They released QuakeEd 4 (i don't know what happened to the other 2 :-P) which they used for Quake 2 [2]. They also released the code for that which is what Robert Duffy used to make QuakeED 4 Radiant that actually made id hire him (you can read an interview with him here before he was hired [3]). The original editor was written in C and used straight Win32 API with a bunch of floating windows while Radiant converted it to C++ and MFC. AFAIK even though it was converted to Gtk through GtkRadiant, the MFC branch survived even in Doom 3 (which was embedded in the game and launched through the console).
[1] http://www.gamers.org/dEngine/quake/QuakeEd/source.html