So the idea there only need be a few forms for a strong system still rolls around.
Now I like my system, which is why I continue to practice it.
But let’s think again on the process.
There are many techniques in many countries which cover the same material as Okinawan arts. Some use forms, some don’t.
To rethink the question one might say why use more than one technique series as enough for anyone.
Now theoretically all one must do in know how to insert that technique into any attack and conclude it. Sure that takes intense training, but then what dosen’t.
Then to cover the basis of if someone works out which technique you may use, you cover your basis and periodically change the technique. That forces you to keep retraining yourself to remain fresh. You would also have your last technique on tap to remain unpredictable.
Obvously you would not teach your student(s) your technique, instead guide them to developing their own technique. Using past techniques you had master and discarded from use to continually test them.
A theoretical consideration.