granted I don't know much about programming so you are most likely right. However the issue of voice actors does matter. Unless they were to have one or two voice actors for each race the price would be very expensive.
Probably somewhat more expensive to do, but not incredibly much. If they had 60 voice actors as opposed to 10, each actor only has 1/6th the work to do, so they don't need to be paid as much. And regardless, they already have these voice actors available, since they need to voice the whole game, including those NPCs who just say rumours, so they just use the same ones.