I was involved in another mmo's private server scene- what happened there was the source code for servers would get released after a server is taken down (whether by DMCA, or just pure infighting), then people build on top of that, then repeat. I would say a vast majority of the source code is not released to the public.
Payment to devs could be considered profit, but profit for the actual people, not the project as a whole and its owners. Also, remember, it's still work, even if it's work on a game. There are reasons not to call pay you get from work "profit"