Deno is a lot better than Node.js because it has no build system, it "just works". But you still have to know about Linux and the terminal to use it, so no matter how much better they make it, the deployment method alone rules out a lot of PHP users. I agree there's still an audience for PHP. Facebook using it is a fluke though, and they wrote their own version of it (Hack) to work around it. Still, I concede that PHP can scale, especially with php-fpm.