Famously Marx never really explained his post-capitalist state - the inevitable communism that history led him to believe we were heading for.
He talked of a transitional socialism with progressive income tax and 100% inheritance tax. He also wrote reams on the inherent contradictions of capitalism - how the drive for more profit would lead to higher inequality, ever greater crises and eventual collapse. But apart from 'proletarian dictatorship' and 'proletariat owning the means of production', little on what comes next.
To the dismay of his followers, Marx seemed uninterested in hurrying along the process. And since he thought it inevitable in due course, perhaps that was understandable. Marx never gave a specific date for his prediction though I doubt he thought it would take this long!
Marxism with its predicted capitalist apocalypse and communist heaven has replaced religion for a lot of Marxists, which perhaps explains some of the animosity between the two. For his part, Marx was sympathetic to religion, seeing it as an understandable though misguided crutch for the poor. An 'opium' giving relief from the daily grind or some hope for their future.
In fact it seems clear that something has kept capitalism going longer than Marx had in mind. The truth is there has never been as clear a dividing line between capitalists and the proletariat as Marx indicated. There is some overlap, especially in developed nations. The democratic process and the Soviet rival has curtailed some capitalist exploitation but as the dividing line again gets clearer and inequality grows, Marx's prediction of ever greater systemic crises seems prescient.
So, maybe we are closer to communism than we think, even in the ultra capitalist US, 30% or more of their economy is state driven. But of course, ownership and control by the state is not what Marx was getting at. The so called communist countries that gave Marx such a bad name much to western capitalists glee, were only ever state capitalist in reality. And there is no doubt that their version of capitalism was not as efficient at production as western capitalism proved to be.
What Marx was talking about was quite simply giving power over the economy to the workers, something that was as far away in the Soviet Union as in the US.
Communism, I think, simply means democratic control of the levers of power - workers on the board of every company deciding remuneration, truly democratic elections without bias and with every vote of same worth and parliament truly reflective and representative of the electorate. A society where the basics of life are evenly divided and those at the top are not allowed to exploit their position to further their wealth and status. Hopefully Marx was wrong when he said it would take a violent revolution to achieve this.