Ever since structured programming was invented, proper indentation is the first basic thing that makes code more readable. It's so basic that people don't even seem to think about it.
The idea that Python programmers wouldn't indent their source code properly if not for the language rules is ridiculous! Same as all other even remotely competent programmers.
Python's indentation rules don't make Python code more readable, because proper indentation is the norm in any language. And if you have to be forced to indent your code, no language can save you from yourself.
All well written programs are indented properly, but not all properly indented programs are well written.