The other two thirds are in administration, research, support for research, various mandatory equal opportunity type jobs, building maintenance etc. I suspect that the ratio of teaching staff to non-teaching staff are much the same in most Universities and that teaching staff everywhere spend a lot of time on non teaching activities. This newsletter supports the view that computers can help education and can make it more efficient but not through any quick fix such as reducing the amount of time instructors spend with students. Life is not so simple and efficiencies come in small steps. Email is great because it is an efficient way of passing messages.
Word processing is great because it makes it quicker and easier to prepare documents.
Online quizzes are great because they can be reused and shared easily between many people and marking is not required. The internet is great because it enables us to easily share information and experiences and stop reinventing the wheel. Attempts to reduce the ratio of instructor time to student time are misguided and doomed to failure. Efficiencies and cost savings can come by reducing the overheads associated with teaching and perhaps getting more people in Universities involved in teaching and less in the peripheral activities associated with teaching. Unfortunately this is hard work and the benefits come in small doses.