Men as a group are inherently selfish and exploitative. And they care less about their children than women do.
They focus on the tasks that bring them material recognition, public praise or enjoyment and leave the rest to someone else. Training for a marathon or putting in the hours on an important work problem - they've got that! Sorting the World Book Day costume - nah.
This would only change if the ball was dropped - for example, the school phoned because their child had no packed lunch or their child was obviously sad or angry because they didn't have a costume. Some men might step up then, especially if inconvenienced. But women care too much about their children to similarly drop the ball and so will usually make up for male inadequacies in parenting.
The thing is - men don't just behave like this in the home but at work too. If they can offload the routine, unglamourous tasks that don't get recognised onto women in the office, then they'll do this. There's a whole body of research about how men/women behave in the office which is fascinating (and mirrors what happens at home tbh).
So men don't just expect women to facilitate them at home, but in the office too.
The decent ones might do some stuff if asked specifically to. But it has to be specific tasks. So that they can then go back to doing things which are important to them.
The saying is "A woman's work is never done" not a man's work. Women are the only group in society who many people think it's ok that they should have absolutely no leisure time.
As to why men have this sense of entitlement, I suspect that it's become ingrained over centuries and goes too deep to be easily challenged, especially when women are socialised to be collaborative and giving.
If I was in charge, men would be forced to report with their young children to mandatory weekend playgroups 4 times a month to give women some time to themselves.