>I honestly love Ruby and Ruby on Rails, but I can't understand why companies like Shopify and Github go through so much effort to scale Ruby especially at their size. Maybe I am wrong, but couldn't this effort be put to rewriting parts of it in a more performant language like Go or Rust? One has to imagine that they have a large code base, how much developer time is spent writing Tests for Ruby? How much time was spent debugging odd monkey patching gems over the life of the codebase?

Me neither, especially there is crstal, a Ruby like syntax, that runs 3 times fast than go. Invidious, (youtube proxy) is written it it. Ruby developer ought to just switch to that for speed.