Unless you're in school leadership, it's hard to see the complexities of this.
In my old school (primary), I changed our attendance system from individual attendance certificates and prizes to class ones. Having a child with a medical condition, 100% attendance certificates wind me up. The top 3 class attendance winners were put on the newsletter. The top 3 and "better attendance since last week" classes were shared in assembly and all of those classes had 5 minutes extra play on a Friday. Every class had a reward several times throughout the year.
The local authority link person was hard on me, and therefore the school, because I wasn't doing enough to improve attendance, and making it worse in her eyes by getting rid of the 100% individuals. I only created a "top 3" classes as she was threatening to mark our self assessment down as "we weren't working with her, nor actioning her shared expertise"
When you get a whole school overview, you see the patterns. The biggest chunk of absence are the parents who don't send their child in, because they think they've got a sniffle, repeatedly and regularly. They're too tired. I heard them cough last night. They wouldn't eat breakfast. One child was at 60% attendance for these sorts of reasons. Other end of the spectrum are parents who can't be bothered to get their children into school as it's too much effort. Kids stay home bored, and learn the lifestyle to pass onto the next generation.
Families taking 2 or 3 term time holidays a year is another big contender. My current school has siblings off for at least 8 holidays a year, ranging from long weekends to fortnight's away. They've already had 3 holidays since September.
Children with long term diagnosed medical conditions normally have parents desperate to get them into school when they can, as they're aware of how much education they're missing due to all the appointments or days needed at home for treatments/recovery.
Things can be done though for the ones who are persistent absentees. I've recently undertaken research for my Master's, actioned it in my school, and seeing the rewards. Slowly getting there and seeing change with some of our harder to reach families.
@Fantasia99 Keep reminding your son that learning things at school every day is far more important than a new book for the classroom once in a while. And feel free to tell him that other head teachers in our country think his school is running an unfair attendance system because I agree with him!