Earlier quoted context omitted.
What in the world does language in which the site was made in has to do with success? They were never acquired for technology - in fact, go read about their setup on HA, it's very standard stuff. If you build a product that gets traction and solid user base with some viral aspect in step 2, you will sell - even if your app/site were made in QBasic.
This kind of careless, selfish attitude really pisses me off. If I walked into a doctor's office for an operation, saw a tray full of old rusty instruments, was told by the doctor that they were "good enough" and that I should just worry about the result then I would not only walk out of that office but also file a complaint with the hospital. If you're selling your services as a professional to clients you owe them…
PHP isn't a good language but it's not so bad to be unusable. I think you're really overstating the problems with it.