I thought that initially, but long term it looks better. After all, there are lots of different book publishers in the programming/tech space alone and they're all doing OK. With their potential to reach even larger numbers of people further down the skills ladder, these interactive tuition sites are still at the leading edge of a potential explosion of providers (solely IMHO, of course).
Codecademy offers jump right in type of learning, (interactive), while the others seem to have a different style(a lot of video, along with interactivity).
Everyone learns differently so there is the avenue for many.
codecademy.com, codeschool.com, teamtreehouse.com, lynda.com, et. al.