Tried to follow the php|tek twitter but as has been quite typical lately the Twitter service continues to be sporadic.
I partially agree with Blaine Cook's blog post that languages per-se don't scale on their own. However, there are two things that immediately jump to mind:
a) It is much easier to find people who have actually scaled PHP applications, especially in the bay area.
b) Over the past years PHP and its extensions have undergone a lot of tuning to enable them to scale more effectively. This includes optimizing file system access, memory management and various other sub systems which will ultimately affect throughput.