These kinds of herculean efforts do make sense at Google's scale (at least from my reading of their papers & blog posts), but are there advantages for data centers operating at smaller scales to adopt some of the approaches used here e.g. custom-built commodity hardware-based network switches, SDN-based central controllers etc.?

EDIT: Maybe a better question is, at what point do you think about eschewing the traditional Cisco/Juniper gear and look towards these techniques?