Maybe, maybe not. The nice thing about adding constructs to a language is that you often can opt in when you do use them. Also, if you have PHP developers, its going to take less time for them to learn async constructs in a language they're familiar with than switching your entire backend to nodejs just to leverage those features. Seems to me like that'd be far more work and cost a lot more.

Its not trivial to just upend an entire system.