> Because here is a quick list of just over 100 things that have to be considered to port and maintain compatibility between the two:

> http://python-future.org/compatible_idioms.html

It's bit a BS, majority and I would say 90% of that you can simply use the Python 3 syntax and both Python 2 and 3 will accept it.

Also many people who program in Python 2.7 already use the new syntax without even realizing it.