Blaming Deregulation from an Alternate Timeline
According to Elizabeth Sweet, “toys are more divided by gender now than they were 50 years ago.” The weird part is that she blames deregulation … without citing any actual regulations that were repealed. (I won't more than mention that, in the early part of the period, the Hays code was still in effect and any regulations would have been anti-feminist.) This goes beyond the assumption “that all good things come from regulations and if [an] unregulated system is good it must be due to the regulations yet to be passed.” In this case, the regulations were never passed in this timeline. Apparently, a deregulation campaign in another timeline caused the increased in gendered toy advertising.
As for why there was a change … I can think of several possible explanations: the Roe effect, more toy-buying decisions by men, more toy-buying decisions by children, etc.