Exactly. I consider myself PHP developer and I would like to stick to PHP related technologies (I think it's enough there) and maybe things like Varnish etc. But currently looking for a job it's common to demand backend (PHP + some DB systems), frontend (damn Angular), server, and some other (Docker etc.). In my opinion it's not the way. At least not for me. And there was the same problem for every single company I worked with: lack of common knowledge and set of common solutions for common problems.