Yes that is true, but are we not also moving towards a post-political age, where 'movements, parties' and yes even states are less weighty than once they were.
This much, though cannot be true:
"this fact does not undermine the validity of the propositions of historical materialism or of Marxian critiques of capitalism as sociological economic-political-moral theory. The theory is pretty much as true as ever."
The subjective factor in history, a socialist-influenced working class cannot be demobilised without that having a consequence for the workings of capitalism.
In the first place, all of the problems of inter-imperialist rivalry and economic crisis would turn much more rapidly into social crises, if the working class was mobilised and putting pressure on the ruling class. One of the peculiarities of our age is that these squalls go on, but are relatively easily managed and contained.
And I am not sure that Marx's account of the rising organic composition of capital is a particularly good description of today's low investment, extensive growth capitalism. Not much 'accumulate, accumulate' at least, not much accumulation corresponding to industrial expansion, more rent-seeking behaviour and clientelism.