It may, and I guess not every job has the same requirements. And 2 parents could technically split the care time evenly and squeeze out 8 hour days by using 16

It may, and I guess not every job has the same requirements. And 2 parents could technically split the care time evenly and squeeze out 8 hour days by using 16 hours of the day and maybe working all night while the child sleeps. Good luck structuring all your team's meetings around one person's schedule though.