That's exactly the joke though. Every time Ruby (or Python) is discussed on HN we get the same old tired question of "why don't they just rewrite in Rust".
But that's some silly engineer tunnel vision, squeezing the very last bit of performance out of a system isn't a goal in itself. You just need it to be efficient enough that it cost you significantly less to run that the amount of revenue it brings you.
I can bet you that moving off Python must have been pitched dozens and dozens of time by Meta engineers, but deemed not worth it, because execution speed isn't the only important characteristic.
So yes, I find it hilarious when HN commenters suggests companies should rewrite all their software into whatever is seen as the most performant one.
It's usually dismissed because companies think short term, and switching languages is a project with huge short term disadvantages and huge long term advantages.
But that's some silly engineer tunnel vision, squeezing the very last bit of performance out of a system isn't a goal in itself. You just need it to be efficient enough that it cost you significantly less to run that the amount of revenue it brings you.
I can bet you that moving off Python must have been pitched dozens and dozens of time by Meta engineers, but deemed not worth it, because execution speed isn't the only important characteristic.
So yes, I find it hilarious when HN commenters suggests companies should rewrite all their software into whatever is seen as the most performant one.