Labour markets and supply-side policies: too much stress put on the WS push factors?
I think it depends on the category of literature you're reading. The category of innovation literature has a lot about supply-side cost changes, and about related policies - you'll find lots of work on learning curves, technology diffusion, harnessing economies of scale. Frank Geels of Manchester does a lot of work on the theoretical side of this.

And there's broader literature on industrial policy and regulation too.