This is the #1 reason for using PHP as your scripting language. In fact it's the only real reason that exist.
So what you're saying is that ASP.net started as weak alternative to PHP but now it's got better? Wrong. PHP can work with MySQL, MSSQL, PostgreSQL, SQLite, Sybase, Oracle OCI8 and many more. Can you say the same about ASP.net? Wrong. You can Use PHP and MySQL with IIS on a Windows server. But not many do, Why? Because you can also use Apache on a Windows server which is far more superior to IIS. Wrong. What are these largest companies in the world that you're talking about? Facebook? Wikipedia? these 2 use PHP! But if you're talking a company that's big and happens to have a website that does not prove the power of ASP.net in any way. And aside from the ASP.Net vs PHP argument you can't seriously be suggesting that Windows servers are more secure than Linux servers!!! Do want me to say who chose to use Linux over Windows? I'll give you a hint, it starts with a "G" and ends with "oogle"! I never said I'm an expert on ASP.net. With that said I know my way around it, I have used it and I have also used PHP. Then I made an educated choice on which one is better as a web programming language and it was PHP. Also I keep in touch with ASP.net programmers and I haven't seen or heard anything that would make me change my mind. That's no excuse. You're telling me a $50 billion company like Facebook thinks that, as you said it, "ASP / C# is without question the most powerful option." and "Compared to .Net and ASP, PHP is like tinker toys. " and "ASP and the .net framwork are worlds ahead of PHP". But when it comes to actually using it they're saying "the hell with it, it's too much of work to migrate now"?! If the people at Facebook were thinking like that the wouldn't be Facebook!