Yes, Python 3.0 was released 17 years ago. But the transition from Python 2.x was only completed with 2.7’s end-of-life, 5 years ago.
"It's still supported" is a strange metric for this. I mean, ActiveState still provides Python 2.7 builds with (paid) support.
And Ubuntu ESM got used as an excuse/"life support" for python 2 via 16.04 until horrifyingly recently. (With a layer of "you can still get ESM for 14.04, we're not that far behind" :-)