We are caught in a Catch 22 situation here. DMUs make sense for relatively small operations due to their flexibility and fuel efficiency, at least in theory. But relatively small operations can't afford to take (and shouldn't take) the risk of developing new technology and the small number of units required make for a high cost per unit. Large operators (Chicago, Los Angeles, even Salt Lake City) that could afford the risk of new technology don't need it - the locomotive hauled 8 car train works very well for them.