It would be different materials - carbon nanotubes, graphene for e.g. offer better properties at the same "nm" and will require different processing techniques thus making it expensive right now in terms of capital investment for mass production. We will see the shift occurring when the cost of extreme UV and X-ray lithography exceed investment required in new materials and processing techniques.
Considering we may just see 10nm cpu’s (and 7nm in iPhones and comforting smartphones this quarter), I have to ask what’s beyond “nm” in terms of lithography?