ADDED LATER. A careful study or newspaper article on the question of whether people have it harder or easier than they did 30 years ago or 45 years ago would try to avoid comparing populations that a reasonable person would expect to differ for reason other than things in the country getting harder or easier. Whether or not my sentence above containing the phrase "are healthier, smarter and wealthier" is true, clearly one might reasonably expect systemic differences between people who have children or will go on to have children and people who do not.
Even if the "nonparent" group were on average more intelligent than the "parent" group, that would also be a reason to avoid omitting the "nonparents" from the older cohort in the study.
The fact that the OP does not even try to avoid those systemic differences suggests that either the author is not sufficiently skilled at statistics to be writing about what he or she is writing about or someone is trying to argue for some conclusion he or she is attached to, e.g., "it is awful how hard things have gotten in this country for the average person" or the article author is making the headline more dramatic than the situation actually is in order to get more clicks.