The classical works of Marxism are primarily an anatomy and pathology of capitalism, and a study of the dynamics of class struggle in capitalist society. As for the many problems and difficulties that would arise, and how they might be resolved, after capital's political and economic rule had been overthrown, when the victorious proletariat and its party organized a state and set about building a new society and a new system, those works say very little. Indeed, they could not have addressed them at all.
A problem can enter a thinker's mind concretely and profoundly, and find a solution, only when objective conditions bring it to the fore.