I don't know about MTH, but Lionel has done RC/battery sets in the past, so never say never. After all, the current systems are really "Radio Control" systems anyway and use the track for power instead of a battery.
I'd like to see them yank the AC side of the equation, along with the sound/control systems (gotta be a burden as far as $$$ to them), and offer engines with a DC motor and lighting circuit. In addition, they could install a plug much like DCC does now so that "niche industry" (or their own if they chose to keep their fingers in the pie) RC/battery electronics could be a simple plug&play feature.