When I had an interview at Apple I asked them why they were using PHP, and what it boiled down to was momentum. They team was able rapidly satisfy requests and could navigate the codebase easily so they had no reason to rewrite it. Which amongst other insights helped shape my viewpoint that the best tool for the job is the one that you are (or the team is) most proficient in. What business is going to wait 3x as long because of technical merits of using a different tool? It doesn't really make sense.