Labour markets and supply-side policies: too much stress put on the WS push factors? In reading several macro textbooks, it seems that most of the supply-side policies tend to be focused on the labour supply side (wage setting curve), instead on the firm/labour demand side(price setting curve).  

In most textbooks, this whole section is devoted to training programmes, wage accords, income policies, the degree of 'coordination' in unions of the economy, etc. 

Almost very few pages,or paragraphs, are dedicated to price-push factors, for the exception of the usual chapter on the oil shocks in the late 70's, which can be seen as labour productivity shock. Almost nothing is said about improving competition, and whatever else can be considered as price-push factor.

Why is that? I maybe wrong, though.

Some may say that there's no too much stress, since the relevant policies are already studied in the field of Industrial Organization. However, my reply to this, is that there's also a field called Labour Economics where many of the effects of the policies for the WS curve are studied, and yet macro textbooks still cover them. Hence, there's clearly an unbalanced exposition in most macro textbooks...
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.