The final version of Python 3.9 is scheduled for release in early October, so Python maintainers believe it makes sense to remove the 2.7 compatibility layers.

Code cells from Python scripts by default will still be executed in a same interactive window, but developers can now configure the Python extension to run separate files in separate interactive ...

But don't worry, say Python maintainers, attackers can only stall your machine even though technically it is remotely exploitable.