What you fail to consider is that there do exist students entering 2 year degree programs who have virtually no computer skills. Maybe they can send an e-mail and do some things on the Internet. They don't really know what happens but they know where to click. And many who may know some basic skills but not others. I'd say the vast majority don't know the difference between an operating system and an application. A good many don't know how to save e-mails, basic word processing. Very few have worked at all with spreadsheets, databases, etc. The difference between memory and disk storage, absolutely no idea. That's the reality of many of the students walking in the doors in my college. You really think I should start with network security when the students don't know how to properly create, save a Word document and be able to find it again later?
Granted those going into IT should know these things, and most do. For those students it's an easy A or they can place out of it. But you have to remember that that course is nearly always a campus-wide pre-req. And many of the students do need to know the very basics of how to use a computer.
You brought up an excellent point, before students are allow to enter the perfect I/T program they would have to meet basic computer aptitude requirements. Of course students will be allowed to take non-degreed courses to reach these requirements and students would be allowed to test out.
I have taught several computer courses and the biggest stumbling block to achieving true classroom success has been the acceptance of students with virtually no computer skills. The last career institute I taught had students that were fiftyish with no computer experience and were actually afraid of computers.
Imagine a fast track computer program that teaches Electronics (DC, AC & Digital), CompTIA's HW, SW & Networking, Novell CNA, and MCSE programs in less than 13 months to students that never touched a mouse before. The students that never touched a computer were a hinderance and drag on the class.