Back in the late 1980s and early 90s I was a TA in a Head Start Day Care. It wasn't like regular Head Start in that the children were there for working parents and court ordered day care and it was an all day program. Maybe because it was a federally funded program, but the rules were quite stringent. If a parent didn't call in when their child was absent, we HAD to call them.
A lot of preK programs and Head Start are federally or state funded. How much they get is often determined by how many children are there. Because of that, they probably take the extra effort to call the parent. I know that when my daughter was in state funded preK, she would get kicked out if she had more than five absences.
In regular daycare though, you have to pay (in advance) whether you are that a lot. I always called when my kids weren't going to be there but I don't think that was the norm. Parents were no call no shows on a regular basis. And I could see parents getting mad at the daycare for "checking up on them". Just my opinion. But I can see why a large daycare would not call every time a kid is out. They are busy taking care of the kids who are there.