Nowadays, as many as
1 in 25 children will have at least one febrile seizure.
In the past, this data was not tracked well and there have been no studies to compare it. But go ask your grandmother, or someone else her age: did she know any child who had a seizure? Even one? Neighbors, classmates, coworkers' children, anything? Ask an older teacher: did she ever see or hear about a child having a seizure in the classroom, in all her decades of teaching? Our school nurse told me they handle at least 2 or 3 a year, from different children, and usually it's the child's first seizure.
Something's going wrong right in front of us.