You're right that PHP has historically had its fair share of "development by copy-and-paste from StackOverflow" developers. However, I've noticed that in recent years a lot of those people moved to the JavaScript ecosystem. It's the latest shiny and the learning curve and time-to-deploy curve is low like in PHP (though, many in the JS community are trying their best to complicate that part for reasons I can't fathom)

Does that leave a PHP community comprised of only people who adhere to solid CS/SE principles? No, but that doesn't diminish the fact that PHP still has a lot going for it. It's easy to get started. You can adhere to solid CS/SE principles with little effort if you have the discipline to do so. It's trivially easy to deploy a PHP application. The documentation is still fantastic.