> I guess its the title I find misleading.

This meme of people on HN judging articles entirely on their title really needs to die.

> My simple point is that PHP has been "mature", in OOP terms anyway, for at least 10 years now

You keep saying that and I keep replying that nobody was ever arguing otherwise.

> so the original author tying that milestone to PHP 7.4 seems weird and outdated to me.

Again, they wasn't. You just assumed they did; presumably because you just read the title and the pre block and skipped over all the rest of the content.