Yes, if you're writing a multithreaded memory sensitive application (or really just any application in general that has performance as a primary objective) then

Yes, if you're writing a multithreaded memory sensitive application (or really just any application in general that has performance as a primary objective) then PHP is not the right tool for the job. It's not a golden hammer, it's just that most websites at their core are simple CRUD apps that initially don't need more than what PHP offers. When you do need to scale your PHP app to tackle these problems, there's no reason why you should limit your stack to PHP. It's OK to not like PHP because it's not a beautiful language but I don't buy the argument that it's never useful.