Actually they do if they have to maintain it or want hire really good developers to maintain it. Not saying PHP doesn't meet those criteria, it might in a given region or situation, but just saying your dismissal of this consideration is way off base. Good luck hiring anyone passionate about good software development or recently graduating from decent CS department to work on your PHP apps. I'm sure you are a great developer with a real passion for your craft but you do realize that plus PHP makes you a very uncommon find, right?