I'm Swedish, working in Sweden, and for the life of me I cannot even comprehend what a version of SQL Server localized for Sweden or Swedish would look like. What does it mean, other than error messages and tools in another language?
Getting date and time formatting, week and day numbering and that stuff correct is a no brainer anyway (apart from being mainly a client issue, in my opinion). The only thing I've even remotely come across is SSIS not having access to every desired locale, which might have been nice when reading CSV files. But unless a localized version were to give me access to EVERY locale, I'll rather make do with the US version.
Just because you're right doesn't mean everybody else is wrong.