为什么没有更多的.NET应用程序使用MySQL或允许使用MySQL的DAO？

I suppose this question could just as easily be applied to PHP with regard to MSSQL. However, with some versions of MSSQL being so expensive, I always wondered, what is the real advantage of choosing it over MySQL for .NET development? Is it really difficult to use .NET tools in conjunction with a MySQL database? Why not create some sort of DAO that abstracts out the differences between the two so that you can use both? As I consider building .NET apps, I'm always wondering, should I just go with MSSQL, and not even consider MySQL as an option?I suppose this question could just as easily be