so basically there is no hope?Most of the problem has nothing to do with seeking the lowest common denominator--it a simple unwillingness to change. It happens in all walks of life.
I learned this years ago as a school teacher. I tried some innovative teaching strategies that were being recommended, and I was stunned at the difference in student achievement. After a couple of years,, my full time job became working in central administration, teaching teachers how to make those changes themselves. The resistance to change was shocking. In many cases, it took the form of open hostility.
IIRC, it was around 1970 that education researcher John Goodlad published a clear description of the problem. His initial goal was to see which instructional programs were the most effective. Previous researchers (especially Coleman) had compared instructional programs by comparing the achievements of schools that had adopted different programs and discovered that there didn't seem to be any real difference. Goodlad did it differently--he went into the actual classrooms and observed the teachers. What he discovered was that it did not matter what instructional program the school had implemented. Once the door of the classroom was closed, many and perhaps most of the teachers just did what they had always done before, ignoring the adopted program.
Other researchers found that classroom teachers tend to teach their students the way they were taught themselves, regardless of any training to the contrary they may have received.
Research by the Annenberg Institute for School Reform at Brown University showed that the open resistance by only a couple of teachers was enough to derail all reform efforts within that building.
Why would scuba instruction be any different?
The only hope I have is that RAID continues to take marketshare. Money is the only thing that is going to get agencies to reform/mandate neutral buoyancy instruction.