The first paragraph is plain wrong. JS is the JS of frontend because there are no replacements. Use a language compiled to it, but still you'll have to know and use JS. PHP on the other hand is a caricature of a language that you can avoid.

The second paragraph is correct, but it's just equally correct for Python, Ruby, Perl, Lisp, Shell languages etc., as they all support multiline strings and string interpolation too. The only difference is that you'll have to wrap strings in delimiting markers, instead of code with <? ?>.

Agreed. I've worked with PHP for years. It's not my choice unless it's a requirement. There are plenty of other more durable and scalable languages for the backend (as you've listed) that are just as easy and quick to get going if not more so.

Isn't NodeJS the Javascript of backend?

+1 for NodeJS, seriously no offence to PHP folks, but Nodejs or Python is not much different from PHP in terms of developer productivity.

The reference implementation of PHP, Zend, is objectively not good (blocking I/O) and encourages server side templating, which is basically something you can perfectly do in the client and serve on a CDN at much lower cost (orders of magnitude lower, for processing, memory and transfer).

That being said, doing server side templating in node.js is even worse since it usually wrecks the entire event loop with long lived CPU-bound operations flushing your server performance doing the toilet.