Interesting point. I don't know. Some thoughts:
I still think that there's a place for teachers. I agree with richard_reitz that individual attention is overrated. That if lessons were good enough there'd be much less of a need for teachers to diagnose holes in students understanding and tutor them. And that there isn't really too much individual attention in todays system anyway.
However, I think that even with these great lectures, there will still be holes in students' understanding, and that using a human is the best way to diagnose and address them. Like Sal Khan has talked about, I think that if these lectures were available, it'd actually free up teachers to spend more time providing personalized attention. I suspect that there's enough of a need for this such that teachers will still be employed.
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
To any future monthly posters of SQ threads, please remember to add the "stupid_questions" tag.