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I feel tempted to drag Gymnasiast into this discussion since he's one of the contributors to the project and might be able to tell us if Joel's streams had a significant impact on OpenRCT2's development or not.
I can't decide between keeping the section and removing it because, while your reasons are valid (RCT2 has been out for at least 15 years and many players have uploaded footage of themselves playing it; the UCES has been out for just as long), Joel may have been a large external contributing factor towards the growth of OpenRCT2—the thing that nags me is that he posted his multiplayer footage compilation at a time when there were few multiplayer servers to speak of (and most of those available weren't password-protected); OpenRCT2 today, on the other hand, has a pretty decent list of password-protected multiplayer servers and I can't help but suspect that some of his videos may have exposed the game to a very large audience and thus contributed to OpenRCT2's growth.
The other reason why I can't make a choice here is partly personal as well—if I didn't stumble across his first "Destroying RollerCoaster Tycoon" video, I would probably have never even bat an eyelid at OpenRCT2, so I don't think I'm able to make a decisive choice or act accordingly in this particular case.