Likely cheaper doing it with two motors vs. one motor and a transmission system to all four wheels. More weight, more friction losses, more stuff to go wrong and less control vs. two motor. Only plus would be larger motors are more efficient, maybe 5% between 2 x 100 and 1 x 200 motor?

Could Subaru put a 200 HP electric motor in an Outback and run the wheels on the existing transmission?