Years ago when my boys were younger (one out of graduate school and the other a college junior) the “superintendent” (don’t get me started on that one

) of their one school K-8 district would have get togethers. Usually some parents, him and a teacher or two.
I went to one once and during the Q&A I brought up that 4th “R” idea. He said it didn’t fit with what he wanted to do…make the upper grades more of middle school thing to prepare them for their “HS career.” I mentioned how many of us picked this particular town and it’s school because the K-8 set up. I then asked the teachers, some who were from the upper grades, how the kids behaved after being outside or gym class. They all said the learning environment was much better for all…teacher and student.
To paraphrase Gordon Gekko…the 4th “R” is good. It works for the kid and the teacher.