According to their annual report (which you can download for free from hitta.se) they transferred Mullvad to the subsidiary Mullvad VPN AB in 2020, which had a revenue of $4M: https://www.allabolag.se/5592384001/mullvad-vpn-ab

Good catch. 2021 revenue will probably be quite a bit more, then.

Well, i'd assume that only a smaller part of the computer using part of humanity knows what a VPN is. Since they are offering a service out of ideolical reasons, with competitors that advertise agressively, a low revenue/profit is totally fine with me. Enough to keep the lights on and build reserves. Citizens of rich countries can be contended with what they have, which is a lot if you look at the other 90% of humanity. Even if, you are "poor" by your counties standard can still feel rich, content and happy.