Nationalisation isn't inherentily neccessary, although in practice it might be; this would simply be due other requirements of a socialist system and not the treatment of nationalisation as a end in its self.
Similarily to nationalisation, a abolishment of fiat currency, and usury isn't strictly neccessary for the establishment of socialism but helpful to the extent to which is helps resolve other goals. Rent can continue quite easily in socialism while using Riccardo's fomulations, that is that rent is a price paid do to decreased cost of production in a area which seperates the value of a hours labor from that of the socially neccessary labor time for producing a product beyond that of what skill or tallent would do otherwise.
Cockshott neither propose a system of work's self management nor rejects one. CyberSyn wasn't a system of worker self management but rather a way to reduce delay in reaction to problems low in the chain of production.
I'm not sure why profitable is in quotes here, are you doubting that industries having varying organic compositions of capital? Perhaps what you mean by this statement is that certain neccessities should be provided by the state such as food, healthcare, education, and other staples of social democracy. To some extent this might be neccessary inorder to seperate wages from the labor invested in a individual, but other than this does not seem vital in a society where individuals earn the full value of their labor (minus some fee for the reproduction of the means of production).
So what is the real rule?
Workers are entitled to the full value of their labor minus any cost of the reproduction & extention of the means of production (and of further workers if students are provided with wages, healthcare is provided, etc).
The socialist mode of production is the only thing that defines socialism. To the extent to which individuals give according to their ability and receive according to their contribution is all that matters.
