There is quite a bit of literature on sustainability transitions that is explicitly concerned with sociotechnical innovation, particularly (but not exclusively) in the area of community energy initiatives.
The "why," if not the "how," of innovation is simple: it is the purpose, reason, or cause behind whatever adaptation, improvement, or invention is needed and successfully applied to beget from scarce resources valuable outcomes that meet explicit or latent needs. And so, might it not be that demonstrative effects are the outcome and not the precondition of successful innovation, be it sociotechnical or not? If so, some make the case that approaches such as design thinking can from the onset help us see, shape, and build better (for subsequent demonstrative effects effects).
I have not seen many studies on the demonstrative aspect. One possible item is in Brown, H. S., & Vergragt, P. J. (2008). Bounded socio-technical experiments as agents of systemic change: The case of a zero-energy residential building. Technological Forecasting and Social Change, 75(1), 107-130.