They are a German GmbH and must publicly state their financials: https://www.northdata.de/win%C2%B7rar%20GmbH,%20Berlin/Amtsg...
Looks pretty profitable to me.
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.
That’s surprising. Seems there is a niche for everything.
They're one of the few companies that actually manage to sell "boxed software" (i.e. has not changed much in years but new customers keep buying it)
That said, Windows users should use 7-Zip. Better compression format, unpacks more kinds of archives