@bitecode I admire your impulse here, but this would be a usability disaster unless "text open" were the default and "bytes open" were something else.
The reason is that you very rarely actually manipulate files as bytes - you mainly use some sort of abstraction. Almost certainly "put some text in this file" is the most common abstraction people use. "Why do I need to always call the `.text` method every time I open a file?" would be one of the top complaints about the ergonomics of Python.
Not to mention people would probably get confused and start using bytestrings.