Since the ERJ-135/40/45 and CRJ-200/700/900 types are all rear engined, and since the regional operators have been one of the few parts of the American industry to make money in recent years (LCCs being the others) I don't see a correlation between "rear engined" and "loss making".
In fact, given how many loss making flag carriers operate wide bodied aircraft, which are all underwing engined, it's closer to being the other way around - operators of rear-engined aircraft may be MORE likely to be profitable today.