It's nonsensical because you misunderstand it. He is saying he thinks two or more of them ought to combine efforts in order to prevent all of them from failing.
Two of them "combining efforts" is removing one. That is no different than one of them "failing". That is the point. Contrary to armchair OS designer belief, you can't just say "hey guys, stop working on your project and go work on someone else's because I don't know what I am talking about and think this will somehow help something". Go tell linus to start working on mercurial because you think he should. What is the result of that conversation going to be?
