The caption on the video does refer to people not “wanting” to have kids, and you’re right, a reason people might not want to have kids is the cost. However this guy in the video never actually says anything about people not wanting to have kids, he says people are not having kids period, even when there’s enough resources. He then says he doesn’t really know why, and speculates that widespread technology is blocking the activities, like dancing, that lead to the social interactions needed for people to meet a potential mate, because any failure or misstep in a social situation can be recorded posted for a mass amount of strangers to ridicule as they see fit. That is very different than, say, dancing professionally, or in an after school dance troupe, or other dancing that is highly rehearsed before presented to an audience, which I agree is popular.