Yeah, but nobody's targeting Python 3.0; I think the point was that the Python crowd is likely to exclusively target current versions and lean on 3.6 and under being officially EOL.
If you are running a 10-year old version of python 3, and you try and install some recently written python 3 application, it will never work - you'll be stuck in dependency hell, even getting pip to run may be a challenge due to outdated certs or TLS versions.