https://www.techempower.com/benchmarks/
But even if both of your points were true, the point is to look at what is happening in other languages and frameworks. Every day you spend learning about PHP is a day that you are not learning about the languages that are really moving the industry forward to interesting new places. Ask yourself, honestly, how many interesting new ideas will you learn from studying PHP, versus the more versatile (as in more platforms, and also the frontend) languages such as Javascript/Node, or the more innovative such as Go or Rust or Clojure or R or Julia? And I'm not even mentioning the more experimental languages, such as Shen or Lux.