Re: Why do teachers stop learning?
Learning requires research. Doing research requires good understanding and ability to do the basics. Thus, to be able to continue to learn in Aikido requires better understanding of the basic principles so that experimentation and research can be done. Without the good fundamentals, research cannot be done and learning cannot take place.
One of the best ways to experiment is to teach and use the students as guinea pigs to see what improves their techniques, as well as practicing those things yourself to see how it works on your students. To be able to practice with your students, they must challenge you by making sure they never "give" you a technique. That is where newbies come in so handy because they have a tendency to try and challenge the instructor. It bothers me when people say they would just change the technique if something doesn't work. Research is what is required here, not adaptation. Just because someone stops you from entering into a Shihonage by locking down their arm, it is not a time to use atemi or to just use power to break the lockdown. It is then time to experiment and find out how you really should be doing the technique to make it work better. You do this by going back to the fundamental principles of Aikido and finding out which one you are missing.
Shihonage is a good example. I now get my students to lock down their arms every time I do a Shihonage demonstration to make sure that I am incorporating all the principles that I need to in order to be able to do the technique. In this way, I have researched and found out what principles of Aikido I was missing in doing my Shihonage and have improved it tremendously. The same applied when I asked my students to make sure that I couldn't bend their elbow when I was doing Ikkyo.