The problem is that PHP still has no credible competition whatsoever in core use cases like "take an HTML document and replace static part with something fetched from a database", or "take multiple HTML documents and factor out a common structure that you might want to change everywhere at once later". Of course there exist solutions in "modern, well-designed languages" for these, but I will confidently take a challenge from any node.js, Elixir or Ruby developer on who can get it done faster.
Sophistry about how my solution won't scale to a million users per day or I should have used their framework from the start rather than having a bunch of HTML files won't matter to me nor the <10k people I expect on my website. In many cases, modern languages and frameworks drive adoption for themselves by tricking you into solving a problem that is not actually the problem you have, but they happen to be adapted to.
Sophistry about how my solution won't scale to a million users per day or I should have used their framework from the start rather than having a bunch of HTML files won't matter to me nor the <10k people I expect on my website. In many cases, modern languages and frameworks drive adoption for themselves by tricking you into solving a problem that is not actually the problem you have, but they happen to be adapted to.