Python is backwards compatible. I have reams of code I wrote in python 2.3 that still works in 2.7 without modification.

Also, python (aka python 2) and python 3000 (aka python 3) are considered two different languages. It's not reasonable to consider them one language and then complain that they are incompatible. Python 3 was created as a new language (and should be treated as such) precisely because it breaks compatibility with python 2. That was the intent of the language authors.

You blame the authors for recognizing limitations of a language and inventing a new one to overcome those limitations.

If the FORTRAN authors would have done that about 30 years ago, we all might be programming in FORTRAN.

James