> That startup was much more than just that front end, wasn't it?

It was what 99% of all customers saw, and it was practically bug free for 6 years. What else do you want?

I built and maintained it primarily as a single developer. Yes there were other parts to the company, but both Slack and Facebook were started up purely on PHP - so there's no reason to suggest that you still can't build up $50m companies on purely PHP code.

Anyway the discussion from the article is whether it would have been better to write it in Java. I can't see what benefit Java would bring.