The twenty year span of the book and TV series is the extent of the non-technological age, post-flu.
This is alluded to at the end of the book, but not said outright. We only see a small part of the world. Not long after the story ends, things start to pick up again. Some group, somewhere, has a factory up and running and is working on refining fuel.The TV series is an alternate universe version of The Martian
Mindy Park in The Martian is who Kirsten Raymonde would have grown into if the plague wouldn't have happened.