Although there are some great examples of games being improved by mods - Skyrim perhaps being the most obvious - ARK: Survival Evolved is a great contemporary one. From day one it's had people adding new dinosaurs and content to the game, though of course only those running private servers could really benefit from that high-level of customisation.
Not any more though, as the developers of ARK, Studio Wildcard, Instinct Games, Effecto Studios and Virtual Basement, have now added a whole new island/continent to the game, but none of them made it. The map, known as The Center, is a mod plucked right out of the community, with the developers paying the creator a hefty fee, as well as signing them on as an official employee.
This is modding leading directly to employment. While it has happened before, it's not the most common.
Although there has been no disclosure on how much the fee paid is, we have been told that it equates to "many months," worth of work as a creative, so a few thousand dollars presumably. Not bad for someone who initially just wanted to create something fun for people to play.
The other mod and modder that the ARK developers have hired on was Primitive+, which adds a tonne of new items and constructible structures to the game, making it more about survival than stomping around with your dino pals.
What kind of mods do you think ARK will pick up next?