It's a sort of reverse natural selection. The people writing PHP these days for whom the last, oh, 15 years or so weren't enough to stop writing PHP.
What I found interesting was a period around 2008 where PHP still had "easy deployment" as a pro in its belt. Some enterprise level projects looking for easy adoption chose PHP and tried to build as they would have in Java.
One example is Magento, and arguably it was the right choice at the time and has given it enduring popularity (if not endearment) for nearly a decade.
As more software engineers took web applications seriously they brought best practices and tech stacks with them, and you can see the PHP community really strive to level up.
But if I were to make a bold statement, it is web development in general that struggles producing solid reusable work. You see it in all languages. The only ecosystem I can think of that isn't disparate islands of unique wheel factories is Ruby, and that seems to be because people learn "rails" not ruby.
You are on the mark for Java like OOP becoming popular in PHP. I think there are more people trying to do enterprise level work with PHP and they are taking lessons from existing software engineering practicies.