Pre-existing models/art is something that is a huge work effort. Not to be undervalued. If one can get those for free, it can be the reason some game exists.

Take Auto Chess for example. I can imagine programming that DOTA 2 mod was an effort one or few programmers did as a hobby at first. If they would have had to either pay or network with artists to create the art and other people to do marketing, it would have been a lot more than a hobby.

[–] MudMan@fedia.io -1 points 2 days ago

"One or few programmers" is the key part of that, though. I'm not saying every modder should get into game development out of the gate. Modding is a great way to dip your toes into gamedev without having to do all the teambuilding and groundwork of putting together every piece of a game.

But some mods get so big they do have a full-on dev team. Nothing wrong with spending some time getting proof of concept that the team can do the job, but if you're spending years with a full team completely overhauling a game... I mean, get paid, man. You're doing a whole ass job at that point.