I don't think Node is faster than PHP because you can pretty aggressively optimize PHP. Between opcache cache, hot interpreters, JIT, frankenphp...

Chromium optimizes JS, sure, but not for that use case. It optimizes it for the frontend. I'm sure a huge part of that is how fast you can compile it - which means less aggressive optimize. I'm sure chromium absolutely does not optimize for long-lived JS processes.

Although, to be fair, I don't actually know which is faster. Just based off of my own experience, JS has been shockingly slow, and PHP quick in production. But that could be React clouding my view.

All in all, JS and PHP are pretty similar. The same stuff that makes JS slow is the stuff that makes PHP slow. Its not like JS has some magic sauce to turn an interpreted dynamically typed language into a performant one.