PHP is the most widely used language for web application development. In spite of this, nobody uses PHP to develop desktop apps. I suppose one of the main problems is the lack of an easy to install, prebuilt package. There were only a few win32 binary releases, and each of them was released after a long period of silence. This is not a criticism to php-gtk developers (a BIG THANK to everyone involved), but users always had the feeling of a dead project.
The real problem is the lack of enough developers, packagers, doc-writers, so I decided to contribute some documentation to build php-gtk on Windows.