Yep, same here. We moved after 9th grade from a 7-9 junior high school to a 9-12 high school, so I was never at the bottom of the popularity chain. At least not for that reason. 
Incidentally, the school we moved from only relatively recently changed to a 6-8 middle school, some time in the last 10-15 years. This was in Oklahoma, and I’m just mentioning it as a data point to illustrate in some states it definitely happened later than the '70s.
In our (me as the parent) district High School was alway grades 9 - 12 but the Junior Highs that were 7,8 were replaced with just two Middle Schools of 6 - 8 about fifteen years ago. A large part of the rationale was that with two years the students are either in a year in which they are mostly adapting to the new place or one in which they are anticipating leaving it, developmentally with that age cohort being difficult enough to work with as it is.
Historically the concept I think was most rooted in an explicit recognition that those peripubertal years are not just a transition between the prepubertal socioemotional and cognitive demands and adolescent ones (the Junior High transition to High School model), but a period of specific and often herkyjerky issues of its own.
It began to take off in the '60s but many districts were like ours and did not fully transition until late '90s or the aughts (in our case coupled with a funding referendum to pay for new buildings to house it). My impression is that standardized testing has undercut the model some and I am not sure if districts that embraced the model earlier or more fully had any measurable beneficial outcomes to show for it. Many “Middle Schools” now are not of the classic middle school philosophy.
Growing up late '60s my “Jr High” was 6 - 8 though and was a continuation of the same cohort (plus minus people who moved in or out) that had been together since KG. It had been structured that way for decades already too. FWIW.
When and where I was in school, middle school and junior high school were separate things. This was a small town in western New York circa 1980. The middle school and junior high shared a building (separate wings mostly, except some common areas) but had different organization and different principals.
Primary school = K-3
Middle school = 4-6
Junior High = 7-8
High School = 9-12
In California my 7-8 grades were at an “Intermediate” school.
This was more or less the meaning in my area waaay back when I was a kid. But, again, less than 100% uniformity.
In any case, there was no concept of “dropping” one term for the other. Both were in simultaneous use.
I went to a junior high school 7-9 grade.
10th grade (1976) was at the former black high school. It had been built only a few years earlier There was a shuttle bus for students that had a class on the main campus. My Western Civ class was on the main campus. 30 mins wasted (round trip) on a shuttle bus.
11-12 was the main high school.
It wasn’t large enough to accommodate all the high school age kids after segregation ended.
The town’s high school was enlarged and the old black high school also got enlarged and is now a middle school.
Our district years ago used to do elementary K-6, middle school 7-8, and then high school 9-12. There was a separate freshman center for the 9th graders. When my daughter was in K, she’s a sophomore now, they changed it to K-5, 6-8 and 9-12 with no freshman center. I think numbers came into play because the freshman center is now one of our middle schools.
I always thought having 3 grades grouped together was better than 4, so the age range isn’t as great, so 7-8-9 as Junior High and 10-11-12 as High School made better sense.
Where I live now, it doesn’t matter. All grades, pre-K thru 12, are in the same school, and not greatly separated by wings. Any bullying that might go on is highly criticized and suppressed. In some cases, having all grades together works well – families don’t have a logistics problem, and they can all share the same bus when they leave home.
For us, it ways always “intermediate school” for 6-7-8, with high school being 9-10-11-12. There were some junior highs in certain districts (7-8-9) with the high school being 10-11-12.
Now, all of the former intermediate schools have been renamed “middle school” for some reason. Maybe confusion over the “intermediate school district”? But that seems far fetched.
I had the misfortune of staring high school in 9th grade, then transferring over the summer to a 10-11-12 high school in a different district. The 10th grade was like being a freshman all over again! Not to mention that my 9th grade curricula were high school level in my first school, but only junior high level in my new school.
I was a year ahead of everyone else in every academic respect, and with some stupid “every child can learn” philosophy instead of useful stuff like “advanced placement” and “college prep.” You don’t need these, because “every child can learn.”
As pointed out, there is no single uniform or systematic rearrangement of the designations. Administrators make decisions based on what they see as their districts’ needs and goals as to how to respond to the different requirements of the different age groups, and whatever parameters the regulators may impose on what is “primary” vs. “secondary” level education.
Growing up, we faced parallel tracks depending if we were in the public or private systems.
Public school had Elementary K-6, Intermediate 7/8/9, High 10/11/12. Intermediate and High were classed as “secondary”
Private schools mostly had the two-part system: Primary K-8, High 9-12, with 6/7/8 being a sort of “upper primary”.
In general, the distinction between philosophies is that Junior High is run like a high school, with students attending individual classes and no smaller groupings of students. In Middle School, students are grouped into pods/teams/groups with a set of 3 or 4 teachers that cover all the major subjects. It’s a transition between having a single teacher in elementary school and the individuality of high school.
Obviously, different schools embrace all or parts of the philosophies, and naming conventions aren’t universally applied. You can see parts of each approach in many schools regardless of what they are officially called.
I went to a funky school system at one point where elementary was 1-7 grades and high school was 8-12 grades. It probably doesn’t make much sense to have a school dedicated to just 2 grades (7th and 8th).
I asked this very question in an educator’s course back in college. The professor said it all has to do with changing populations and available buildings. If the population dwindles, as it had in the surrounding counties there, a school system might have to use a building for maybe 5th-8th grade or 6th-9th. It didn’t make any sense to call those buildings Junior High Schools any more, so they settled on the Middle School moniker. Regardless of the building, ninth grade counts as High School in the U.S., as far as grading and graduation goes.
You may have heard of the “true middle school concept” which was dreamed up to try to fit this situation. It’s a back-formation with no merit, IMHO.
I went to school on Long Island in the mid-1990s, and grades K-6 were Elementary, 7-8 were Junior High, and 9-12 were High School. The actual name of the junior high did have “Middle School” in its full name, though it was always referred to as “junior high.”
My schools used the ES K-6, JRHS 7 -9, and SRHS 10-12 format, and I graduated in 1975. By the early 90s, though, I know my old high school was accommodating ninth grade. Regardless of the fact that I was still on a junior high campus, the guidance counselors (and my parents) made it crystal clear that for the purposes of college admission I was now in high school, and everything “counted”.
The change the OP is asking about, at least in my area meant that the middle or “second” school changed from 7-9 to 6-8. Maybe that was one of the goals. Starting JRHS in the seventh grade, everyone felt intimidated by the “A9s”–they were as big as adults, for crying out loud! Changing to 8-6 would have alleviated that issue somewhat.
*The system of “A” and “B” classes, and winter graduations, was just about over at that time, but we all still remembered it in 1972.
This is similar to what happened with ours except 6th grade was tacked onto it because there was enough physical room.
Another reason for middle schools is consolidation, especially when schools were closing (at least in my area) after the baby boom drop. My town closed its two junior highs, established a middle school (grades 6-8) at the old high school, and built a new high school to accomodate grades 9-12.
Now that we’re having a mini baby boom in the area there’s been talk of re-establishing junior highs in the name of “neighborhood schools” and smaller classes. I doubt it’ll come to pass as a new middle school was just built a couple of years ago and two elementary schools a couple of years before that.
I don’t think this is accurate. The concepts of middle school are distinct and real. I’m not sure what your professor was saying.
My school district had Elementary 1-4, Middle 5,6, Jr High 7-8, High 9-12, a private school I attended was k-12 however was divided by building section, elementry section was k-5, grade 6 was in the newer building section, however was run like a elementary segment (one main teacher, students stayed in the single class), 7-12 was the class switching grades in the new building section . The space in the buildings I’m sure had something to do with this, but also the age ‘catagories’ of the children, trying to divide them by development stages.
My school district changed things around every couple of years depending on class size and how many rooms were available at the elementary school that was mostly rented out (part of it was a daycare center and part was another school district’s elementary school). Things settled down when I was in 5th grade and they got back full control of the second elementary school.
In my town they always called it Middle School. Even back in the early 80s when I attended it. I saw it referred to as Junior High on TV is shows and always assumed that was just a regional difference in names.