Actually, the Kahn model by itself could not replace classroom teaching entirely - Kahn himself said that was never the original goal of it. At the moment, it is designed to enhance and complement classroom learning. In order for an automated technology to make classroom teaching completely irrelevant, it would also have to replace teacher student interactions and individual tutoring and be able to help with individual questions the way a teacher would. As much as we rip on public school teachers - and yes, of course, tons of them deserve all the abuse they get around here, the Kahn Academy and the MIT open courseware by itself cannot make classroom teaching irrelevant.
A technology that can actually make classroom teaching completely irrelevant would also make scores of other vital jobs irrelevant as well and continue to place millions out of work, at least temporarily while they are forced to adjust and learn new trades. And in our nation, this would damage the economy since, regardless off what we prefer, we are not at all prepared as a country to have these Americans go without food or shelter of any kind while they learn these new trades and make themselves employable again.
At MIT, EdX is now the big thing.
Education will eventually go fully online except for things like laboratory work and physical research, etc.
So will management, sales, etc.
You need to study this subject in depth and you would not be so worried about what is coming.