I went to school in the 60s and 70s. At primary school, there were rumours about 'Mr G.: The 'Kid Catcher;' ' who would come to see you if you did not attend school. I do not think there were any 'EBSA' cases at my primary school, but there were only about twenty children in the whole school and two classes: infants and juniors, furthermore, it was a small village and families knew each other. Indeed, both my parents had attended the same, small village school that I attended, many years before.
At secondary school, pupils talked of other pupils 'skiving' or 'jigging' school. It seemed to be almost expected that some pupils would 'truant'. I went into an adolescent unit in my mid-teens, and there were many children/young people there who were experiencing 'school phobia'. Many adolescent boys who obviously had eating disorders were in the unit with 'school phobia' as their primary diagnosis because there was little understanding about eating disorders in males, so their 'school phobia' could in fact have arisen form issues relating to anorexia or bulimia. My husband also stopped attending school regularly just after his father dies, when my husband was 14, his poor attendance was put down to grief.
Both my sons became unable to attend school in their mid-teens. They are neurodivergent. My eldest had one to one support and an EHCP, but his mental health broke. My youngest was not diagnosed and he was unable to attend due to Generalised Anxiety Disorder. The effects on the family were tremendous.
So, based on my experience and contact with other parents, I would say that EBSA has always been present. However, EBSA is also a behaviour with other, often complex issues at its root. These could be a mixture of social/familial problems; neurodiversity (not always a 'problem', but schools are not always a great place for neurodivergent children); mental illness and many other issues.
I could go on, but i have already written a short novel.