I don't think it's apathy, it's that the video format is so worthless for this, and perhaps that the plan Lessig is apparently describing doesn't even begin to address the problem he claims it solves. A voucher system doesn't take money out of the campaign process, it only gives the government control of who gets the money - which means government controls who gets elected. That's far worse than the system we have now.
These other countries that he points to have something that we don't have in the US, and that is state-run television. You can't just go giving away stuff, like tv commercials, that don't belong to you even if you are the government. He suggests that it would only involve $3 or $4 Billion a year.
I hope this drive of his fails. It only creates a system infinitely worse than what we have now. The 2012 elections cost a total of $6,285,557,223. Now Lessig claims that spending two or three times that much is taking money out of the process. He is wrong. All he is doing is creating a new bureaucracy to suck up a good chunk of that money for themselves and decide who gets to divide up their leavings.