For me,its not about different ability levels. Its about a 4 year old not being old enough to be in the cassroom environment. As PP mentioned,in SA where I teach, we wouldnt be having this conversation- he would automatically be waiting.
Some kids do struggle at school. It doesnt mean they dont enjoy it, but I have put in many hours with kids who are not yet ready to learn in a classroom environment. I am a prep teacher. This is what I do. This is what i know. I think the teachers find it frustrating because our advice is often ignored,then we are the ones who put in the blood sweat and tears teaching kids who arent ready yet yo learn in this environment. It takes a LOT away from those kids who are ready.