I suspect trying to compute "how much money they made" would in fact have to consider the cost to run/repair them, as others have mentioned. But, additionally to that, I would also suspect that the full algorithm for net profit would also need to factor whether the game was the primary business (i.e. an arcade) or if it was ancillary to the primary business (store, restaurant, bar, etc.) then what non-game profits it attributed to (sodas, candy, food, beer, whatever). I can certainly attest that many stores, pizza parlors, etc., got additional $ from me because I was there to play the arcade game(s).