JavaScript churns more than Rails which churns more than Elixir/Phoenix.
I believe this is caused by “how sound the fundamentals are” (technical debt in the language itself and its stdlib).
For better or worse, you can take 10+ years old PHP code and it'll mostly just work.
I rewrote it in React for fun and not only is it totally out of date, but Github's dependabot has sent me probably 200+ security advisories based on its dependencies.