The idea behind the article is very good and the article itself offers some remarkable starting points.

However I think that it is not always easy to refactor only some parts of the code. As a matter of fact, when you have spaghetti code that needs to be refactored, every part of this code is strictly linked to other code and you end up to refactor everything, because there's not an easy way out :-)

Pipenv is probably the best tool to keep clean the dependency workflow