I won't mention telnet because you don't use it, but in CSV and similar data it is quite a trouble to normalize the data. So instead of 2 possibilities now we 3 to detect.
Please do consider that many software products will not change and they will still be actively used on production environments that you will never have interest about.
And it was pretty clear from the context of norir's comment that they were not talking about legacy software, they were talking about writing new projects/file formats that used newlines as a separator. Just because you want to shoehorn your legacy projects into this discussion doesn't mean that they fit.