I think Rhys Jenkins 1987 slim text as does a good job in explaining why
competitition is not the quantity theory firms. You can have competition
among a few firms. These firms can be reasonably profitable. Mobility of
capital says nothing about number of firms. So competition is independent
of the number of firms.
Whoeever talked about zero MC? Not me. As for technology, economists of
the left or right, particularly the arm chair types haven't foggiest idea
on technology. It is absurd to state that technology always existed --
some tautological junk. Is not technological change a qualitative
improvement in the production process?
Anthony D'Costa