Telltale got burned bringing Wallace & Gromit to XBLA. Microsoft made it impossible for them to keep those releases in synch with the PC releases. (Episode 2, 3 and 4 were released in May, June and July 2009 for PC, but the XBLA versions had to wait until November.) So they've been reluctant to put anything else there.
although we do still have a time machine, so I wouldn't completely rule out the possibility.