Why isn't there a universal separator character for data files?
We could have a field separator, but we don't, because of historical reasons. Most of the characters are brought from the era of typewriters. So we have line-separator ^M and page-separator ^L, and we actually have record separator \037 and unit separator \038 which can be used as field separator. But in reality no one uses that. First if you have a text file like csv, you want to use separators which are visible like , : TAB or SPACE. If your file is binary you are free to do almost anything with it. 

Now it is too late to have a universal field separator. You can have your own private field separator of your choice. Just don't use it in your fields too.