It's more than a bit disingenuous to call Facebook's work on Hack and the HHVM an abandonment of PHP. A big part of the HHVM project was writing a formal PHP sp

It's more than a bit disingenuous to call Facebook's work on Hack and the HHVM an abandonment of PHP. A big part of the HHVM project was writing a formal PHP spec, and features from Hack have been making their way into mainstream PHP (generators in 5.5; static types in 7). It would be much more accurate to say that Facebook has invested heavily in PHP by financing an alternative runtime.