I disagree with your 'wholly unsuitable', I came across this game engine (Garage engine) written in Go which certainly doesn't jitter due to the garbage collector.
So I say your statement is exagerrated, certainly stop-the-world garbage collectors isn't ideal for games, but it's not 'wholly unsuitable' as long as the gc sweeps aren't costly enough to impact consistent framerate. Had they been 'wholly unsuitable' then the XNA platform would have been dead upon arrival.
http://www.youtube.com/watch?v=iMMbf6SRb9Q
http://www.youtube.com/watch?v=BMRlY9dFVLg
https://github.com/vova616/GarageEngine
So I say your statement is exagerrated, certainly stop-the-world garbage collectors isn't ideal for games, but it's not 'wholly unsuitable' as long as the gc sweeps aren't costly enough to impact consistent framerate. Had they been 'wholly unsuitable' then the XNA platform would have been dead upon arrival.