PHP’s evolution is a consequence of its popularity. If people only ever tried to write small, one-off scripts, then PHP would have stayed a small, one-off language. But people kept getting more ambitious. Wordpress, vBulletin, Wikipedia, and others. People wanted larger and more complex applications, and they often required skilled and professional programmers, as well as new language features to help manage the complexity.
But the good news for you is that you can ignore most of that if you really want to. You don’t have to use namespaces or closures, nor OOP or autoloading. You could ignore all that stuff and still write a simple, procedural, one-off script. You could even write a mostly HTML page with bits of simple PHP sprinkled in, just how Lerdorf originally intended. The new language features don’t block you from doing that.