PHP is much more of a static language than a dynamic one. Therefore it has more in common with Java/C++ than with Python, Ruby, or JavaScript. It's also a very pragmatic choice for an OO system.
Why NOT Java?
Since I don't have to use PHP I'm not too upset. I was really just lamenting the state of the world.
PHP is heavily based on C so choosing to make it's OOP features like C++ isn't a big leap.
Plus PHP is still far less enterprisey than Java so maybe the OO model isn't the real issue.
/s
Zend has made a lot of good decisions (and a few painful but livable bad ones) over the last decade.