It's not about being macho or anything. It's about societal expectations. I feel that here in the US this shit is actually seeping into the female population as

It's not about being macho or anything. It's about societal expectations. I feel that here in the US this shit is actually seeping into the female population as well as more women insist on equality with men. So rather than insist on affording quality parenting time to fathers (which IMO is what they should actually want if they want real, actual equality), they give it up themselves. The aforementioned Swedish use-it-or-lose-it model strikes me as sensible. Some companies here in the US offer vacation time in this fashion, without rollover into the new year, and anecdotally people make it a point to take vacation in that case.