As someone who has spent her whole life making a living by writing, I can tell you it's quite challenging, if not impossible, to make the kind of money some of these so-called "writers" say they make. I never believe any of them and avoid those articles like the plague.
I would switch to a 4-day workweek in a heartbeat. However, I have to wonder if I would be able to get all my work responsibilities completed. That might be stressful, but nothing I don't think three days off couldn't help solve.
I'm 50 years old and childless, and I don't regret my choice. I, too, enjoy the freedom to pursue what makes me happy, the time I have to help others when they need it, and the peacefulness of my days.