http://legacy.python.org/dev/peps/pep-3000/Wow... that was 2006. Everything I've read in the PEP and mailing lists seems to imply that the contributors were doing their best to limit the scope of the backwards-incompatible changes to those parts that were deemed absolutely necessary.
The point wasn't to break backwards compatibility to add new, competitive features. It was to make the incremental improvements to the language while strategically correcting some poor, historical decisions. In other words it wasn't a rewrite or a new language.
That there are still prominent, influential Python programmers who are complaining about the bytes object is a shame. However it's a battle that is slowly coming to an end.
The real problem is that the community has been dragging its feet and many frustrated developers are complaining loudly and publicly about it. It's distorting what Python 3 is.