Not as a theorist of communism/socialism but as a or the theorist of capitalism par excellence?
Think about it, in all his books Marx does little in the way of an outline of socialism or communism, he is a critic of capitalism but he is also its champion, certainly a great part of the communist manifesto is taken up with a serious critique of capitalism's opposition, ie "utopian" socialists, often because by Marx's estimation they are failing to give capitalism the credit it deserves and he does heap praise upon capitalism and its achievements.
He felt capitalism was unfair and that unfairness would never be mitigated, therefore the only response to crisis was to abolish it.
I think that he underestimated capitalism's capacity to create such super-abundance that with class divisions intact, inequality, often grave inequality intact, that the social floor would rise as it has.
There's plenty of political pressure to return to victorian conditions, although it can not be said to be off necessity, it is a political question and choice rather than being compelled by objective conditions of production.
It is only during recessions, like this one, when taxation and spending does not come from growth by threatens to eat into the wealth of the richer elites and disturb their status that there is an issue and that is insufficient for popular or an elite wish for change, its not abandonment of capitalism even.
What do any of you think? Should Marx be taken seriously as a theorist of capitalism rather than a theorist of socialism.