I read GP more as "sure they're profitable, but they didn't exactly have many expense to cover so it's not a very useful comparison to make at this point" than doubt in the profitability itself.
E.g. when SpaceX started designing the Falcon 9 the losses were astronomical (pun intended) but a car dealership running more of a profit at the same time doesn't have much to say about which business is doing better.
they're is obviously joking