For me, school became optional over covid.
Had 2 DC in school at the time - one in year 9 & one one year 10. They were sent home on the 20th March 2020 and then didnt do a single thing school wise at all until September 2020. No work sent home, no lessons online etc.
Their school was fantastically shit (and this is a good school in good area with generally involved and engaged parents).
The school year 2020 - 2021 wasnt much better when they went back in year 11 and year 10 - constantly getting sent home, or years groups shut due to covid and teachers not available to teach. The oldest 1 was in year 11 and had missed half of year 10 with no work for over 6 months. Very hard to engage them to study when in their words 'school didnt think it was that important from March - September so why would they think it is now?' I had to sort of agree.
They didnt see the point anymore and to be honest, neither did I. If the school didnt bother with them for 6 months then the feeling was why should they be that bothered?
Prior to this we never took them out for a holiday, day trip etc. I just wouldnt do it as I felt school was so important.
After covid, I changed my mind and so when they were at 6th form (at the same school they attended), we did do family holidays in term time and I felt absolutely no guilt whatsoever. Lesson plans, worksheets etc are now on google classrooms so they can catch up if they want.
I dont blame the teachers, but I would say for a large proprotion of students and families, the 'contract' between school and home has significantly changed and a lot of people dont think its necessary to be in school every day when the were able to miss so much and no one cared then.
This may change for younger children who didnt experience this, but for a large chunk of kids who were negatively impacted over lack of schooling over covid this is their way of thinking.
Schools have also changed for the worst. Large secondary schools so many kids lost within the system, poor behaviour at all levels, either no discpline or over the top discipline, teachers only care about exam results, no aspirational teaching anymore etc.
I know at the school DC attended (through family members who still attend now), there isnt an issue with long term absences as much as frequent short term absences (a day or two all the way up to 2 weeks for a holiday). They are fighting a losing battle as school is no longer a place they feel safe and are inspired to be at. If kids feel ill then more parents wfh so its easier to just keep them at home than before as there are no childcare issues etc.
I dont know how to fix it all, but something needs to drastically change and that probably starts with funding schools properly, ensuring those with SEN are only in mainstream if they can truly cope and benefit form it etc etc.