Birth Rates & Entertainment
I constantly see arguments that the TFR (birth rate) falling is a mystery, and that maybe it's the "phones" causing depression, or not enough $$$. But I know plenty of non depressed and well off couples not having kids.
What I rarely see is the idea that it's modern entertainment in general. 100 years ago you didn't have TV, Movies, Vacations, Video Games, Cruises, etc. Kids get in the way of these. Businesses have a reason to cater to these couples too. They have more money that they want to spend.
Given there are now just a lot more options in life than kids and sex, are people just choosing not to let kids get in the way of these? If so, most of the solutions being attempted would not work, except for obscene $$$ incentives, or banning of various entertainment for non families. Like taking away videogames unless you do your homework and eat your vegetables.
very related EY post