But to keep it running, you don't really need Python 2.8 with new features, right? You need extended support for Python 2.7 - basically, making sure that it keeps working with updated versions of other software (like OSes), and that bugs are fixed.
Those systems are not just sitting there untouched.
Heck, not even 70s COBOL systems are "just sitting there" (they are hooked to newer systems, get new forms, have alterations, etc. all the time), and those Python 2.7 systems have been written 10-15 years before or less.
And they continue to get new subsystems, new features, alterations, etc. In 2.7.
So, yes, people would very much like to get not just "extended support for 2.7" but also the ability to keep running it in newer versions, and be able to take piecemeal adoption of new features to make their life better and eventually organically refactor in their own timeline.