I had that same idea when I was an undergrad (in the USA). The course outcome should be important, and if I can gain the skills/knowledge without attending, then why require me to attend? When I started teaching underclassmen as a grad student, I even instituted an attendance-optional policy.
But then I became a professor and had the luxury of teaching small upper-level and graduate courses. My belief that the instructor was not the source of all knowledge was reinforced, but so was the understanding that *real* learning happened between students. When a student did not attend our discussions, they deprived us all of their point of view.
So, for large lectures, I agree with you. Use the Western Governors University model (sell assessment and certification/accreditation, not instruction). But for small, meaningful classes, I still require attendance.