I wouldn't agree; I think it's more of most people have stuff going on.
That said, I don't think it's a good idea to use C++ for a game project no matter the skill level since many would agree that any performance upgrade over C# is usually not worth the added dev time. The only reason I would use it is to take advantage of the professional grade assets given free from Unreal Engine.
Personally, I use C#/Unity for just about every project (I do full time gamedev), and in retrospect it would have made more sense to start the project in Unity since lots of beginners would likely be interested in contributing however possible, and Unity makes that easier than UE4. One of my current projects is actually an RTS in Unity.
The only reason I'm not right now working hard on OM is because I don't have time to do much more than management and doing code checks/tests. I'd be happy to run or help with the project if there were any willing lead devs and/or artists.
Good luck with C++ by the way! (If only ruby had the speed of C :D )