I think it's because of C++ in large part. For whatever reason there's been weird conventions in different code bases on how to structure headers vs source (lik

I think it's because of C++ in large part. For whatever reason there's been weird conventions in different code bases on how to structure headers vs source (like, put them in the same dir, or have an "includes" and "src" dir that mirror each other, or have an includes dir that doesnt match the src dir at all. Not defending it because it sucks, but I think .NET just inherited that weird interface because its what C++ did.