I would say that the incompatibility is exactly what makes python 3 be python 3. If it could run python 2 bytecode, then it would allow the same ambiguity betw

I would say that the incompatibility is exactly what makes python 3 be python 3. If it could run python 2 bytecode, then it would allow the same ambiguity between strings and binary data as is allowed in Python 2. One of the main goals of Python 3 was to remove this ambiguity, by introducing "str" and "bytes" as separate classes.