Why are there so many fathers willing to give all the responsibility to the mother?

I just noticed so many single mothers busting their butts to be both a provider and nurturer to their kids and the fathers just live their life as if they dont have a kid or they dont fight for their kid. Maybe they pay child support and they feel its enough for their kid. Whats worse is there are parents still together and the mother still does more for the house and kids than the dad. Why are mothers more invested than fathers? Are we raising the boys to do less?
Why are there so many fathers willing to give all the responsibility to the mother?
Post Opinion