You definitely make a good point. My thought was that large legacy projects would slowly migrate to a different language. The news of the recent introduction of

You definitely make a good point. My thought was that large legacy projects would slowly migrate to a different language. The news of the recent introduction of Rust in Linux has me optimistic something similar will eventually happen in other places too. (not necessarily with Rust, specifically) The keyword here is Eventually. I’m thinking this is years away for GCC and LLVM. If the new language has good interop with the old then this doesn’t have to be painful either. A while back, I was working on a large Objective-C code base which was slowly moving to Swift. We quickly got to a point where new code was written in Swift by default. In only a couple of years, we had a code base which used Objective-C pretty much only in the dark corners where code churns slowly.