Marx always knew there would be a transition from capitalism to socialism.

None of these measures abolishes capitalism straight away; each constitutes a partial intervention by the state in the economic mechanism of capitalism, and only in the totality, and over time, are they deemed to undermine capitalism completely. Thus, for instance, the measure ‘a vigorously graduated income tax’ assumes that under the dictatorship of the proletariat there would still be marked differences in incomes – that the capitalist would not be expropriated at a stroke. ‘During the revolution, the gigantic increase in the scope of taxation may serve as an attack on private ownership; yet even in such a case taxation must be a stepping stone to fresh revolutionary measures, otherwise there will be a return to the erstwhile bourgeois conditions.’