[cyberneticcook]

>> I am baffled as to why you'd build your castle atop a crumbling foundation

I think you're using a wrong metaphor. Facebook foundations can't be crumbling just because they're made in PHP. There wouldn't be Facebook as we know it today otherwise. You might say they used a "low quality" material to build them. I see Hack more as a better material, that can also bind with the previous one and make it stronger.