Poor parenting is at the root of this.
I have been in a primary school today near to Newcastle where they employ two support staff to help Reception children catch up skills and cope with school- toileting, eating, playing, manners, managing temper tantrums, talking , not swearing, sitting quietly, enjoying books, being able to put coats on and shoes on and fasten them, washing faces and hands, enjoying drawing/paint. So many now turn up never having done so many basic things. They see increasing numbers who just can't do basic things because no one teaches them. They are not expecting them all to do everything perfectly of course but so many come with very few basic skills.
They have a little boy in Reception who is a terror- shouts if he can't have his own way, swears, pushes adults and children out of the way, had never had a book, is late every day because his mum doesn't get up in time to get him into school. He is very overweight and will only eat rubbish food. He takes anything he likes. His mum (no dad on scene) has social services involvement. Her behaviour is like his. Her father comes up to the school in tempers shouting and demanding too. They all look and behave the same way.
The school are doing their best with him but today, for example, I was talking to a member of staff in a corridor and he barrelled out of a classroom, like a rugby prop forward, shouting and swearing, stormed into the toilets kicking the door and was followed very calmly by a male member of support staff who deals with him effectively. The issue was he didn't want to do painting and craft because 'it's boring shit'. He is a bully and a thug at 4/5. It's hard to understand how a 4/5 year old can have reached this state but it's appalling parenting.