His reasons for not getting rid of the skits is because he wouldn't have anything else to pay Other Joe for. I imagine they get some sort of salary for showing up on streams and doing the movie reviews. Joe basically just pays them to agree with him. In the videos I saw, which I admit is not many and were also the earliest ones, they maybe contributed about a minute total of dialogue in videos that range from 30-40ish minutes. And most of the dialogue was just blindly agreeing with Joe. Other than that, they just nod, and occasionally laugh or repeat something Joe said.
If they have an opinion that disagrees slightly with Joe, he's very dismissive or sometimes "jokingly" insulting to them. To me, it always felt like Joe trying to act like the top dog, but it just came off as sad, especially since they really don't seem to care at all. It might just be the kind of friendship that they have, but eh, Joe seems to treat everyone like that. I know for some of the reviews Joe has also said he purchased multiplayer games for Other Joe or someone else to play for the sake of the review, despite them not appearing in the actual review itself outside of the skits.
I've never watched his streams, but some other people have mentioned they show up more there. They might be more active in those, but I doubt it. For whatever reason, Other Joe is weirdly popular with the fans. They seem to be pretty readily available, but I don't know if that's because they're unemployed or because Joe just schedules his stuff late enough in the day where work hours aren't an issue.