Kropotkin was prepared to concede that it might well be the case that a person who did only one thing, over and over again, might indeed become quite proficient at it. It is not enough, after the revolution, to simple reduce the hours of labor. The Social Revolution must abolish the separation between manual and brain work, give workers control of their workplaces, abolish wage labor. The advantages of centralized production are similarly illusory. Industry is centralized to facilitate market domination, not because of often non-existent economies of scale.
Decentralization is, in fact, more efficient.
Kropotkin, too, argued for such a system in 1873. This is, nevertheless, what collectivists are doing when they recommend the use of the 'labor-cheques' as a mode of renumeration for labor. Today labor vouchers are out of favor, but most socialists still accept the wage system and money, often disguised as consumption credits, as inevitable. The marketplace is, of course, a time-tested mechanism for ascertaining social needs and preferences for goods. The reason there is mass starvation in Africa is not because the market doesn't work to meet human needs, but because our fellow workers prefer not to eat.