Or could it be that no one else wants to open themselves up to liability?
How come nobody else is hacking cameras? Why is it always magic lantern?Why duplicate what someone else has already done? Join in and work on something that interests you or make an existing feature work better.
Canon has (inofficially) conveyed that they have no problem with ml as long as they leave the 1d series alone.
Btw there are other projects adding custom fw to the cameras like 400plus, but for the newer models they joined up for ml. The reason is that the main work is not the actual coding, but the reverse engineering of Canon's digic and DryOS software, both undocumented (thanks, Canon).
It doesn't make sense duplicating all this, and the ml software framework is very mature and easy to use to add something to it - I often do if I want my camera to do some convenient things like auto-switching to fast drive on bracketing or try to stick to max. x-sync w/o risk of severe overexposure like the Canon fw does.