>I'm starting to doubt if we'll ever see another popular language displace the status quo.

That sounds a bit the end of progress. After all, Go, Rust, and Swift haven't been around for that long.

I might be open to an argument that ecosystem effects (libraries, training, etc.) lead to power law effects. But I'm not sure I believe that. I could equally well believe that the sheer scale of software development today lends itself to a lot of viable niches.