Parents are just too tired
One big difference in the last couple decades is that adults are having children later in life, largely due to medical advances, but this makes them too tired for sex. Samantha Lutz is a renowned psychologist and she explains, "a lot of parents feel like they've already done about 50 things they didn't want to do that day, like getting up at dawn, dealing with their child's tantrums. Adding sex to the menu just seems like too much. So we turn to things like Netflix to unwind, which leads to immediate gratification with zero energy expended."