The structure of capitalism can be likened to that of a bed. The productive apparatus serves as the bed frame. Although there is plenty of variance to the exact configuration of the frame, its structure and purpose is the same: to underpin capitalism as a social construct, here meaning the social relations that emerge from the combination of private ownership of the means of production (productive assets) coupled with market steerage of the macroeconomy and the political relations that emerge from them.
Upon this frame lies a mattress made up of the social relations of production. In earlier times the capitalist mattress was heavy and rigid, with class lines sharply and simply defined and social roles strictly prescribed. Over time, as capitalism evolved and got more sophisticated and complex, moving from the industrial revolution to advanced industrial capitalism and then post-industrial production linked via commodity, supply and financial chains to less advanced economies in earlier stages of capitalist development, the social mattress above it developed accordingly, becoming less rigid and more sensitive to variation in collective and individual connections with the productive base. The clear-cut and strongly defined class relations of previous stages of capitalist development have been replaced in advanced societies by a more variegated tissue of social relations that blur class distinctions and add increased diversity to the way in which people interact in and out of production.
As this capitalist bed frame and mattress get more refined, elements previously unnoticed or quashed by the weight of more primitive capitalist relations have begun to be felt. Some predate capitalism, some emerged with it and some are byproducts of its trajectory. These can be called pebbles of identity.
Pebbles of identity unrelated to production in a direct way have existed between the capitalist base and superstructure all along but were previously eclipsed (when not suppressed) by the dominance of socio-economic class identifiers: blue and white collar workers, managers and owners encompassing the proletariat, peasantry, lumpenproletariats, bourgeoisie and what is left of the aristocracy sharing space with entrepreneurial elites.
In the post-industrial, post-modern contemporary era pebbles of identity play a major role in determining social relations, so much so that their presence can prove disruptive to the tranquility of the body politic as traditionally constituted. Identities previously unrecognised become apparent and are acutely felt in social discourse and political action. The question is whether the post-industrial capitalist mattress can comfortably accomodate them or whether it will prove incapable of buffering the inevitable tensions that emerge from the interplay between pre-modern, modern and post-modern identifiers in present day economies. Likewise, the evolution of capitalist modes of production accentuate or reduce the impact of some pebbles of identity over time. Identities associated with agrarian societies may not be not be felt as strongly in post-modern service sector economies. Religion and dialect may diminish in importance as the social mattress of capitalism changes secularly over time, and what were once mere grains of hidden or downplayed identity become prominent to the point of feeling like rocks underlying social intercourse.
The relative import of pebbles of identity is unique to a given capitalist society. In some, pre-modern identities such as gender, race, religion or language are felt more widely than post-modern identities tied to consumption preferences (be it music, arts, food or  automobiles). In others sexual orientation and gender identity overlap and/or compete with activist causes of various stripes. The way in which these are felt is conditioned by the socio-economic class structure embedded in the social fabric of the capitalist mattress.
Most social scientists, including economists, agree that understanding the characteristics of the capitalist frame is a necessary but not sufficient condition for understanding the dynamics of contemporary capitalism as a whole. The question for political analysts and students of social science in general is therefore where to put the emphasis when factoring superstructural features into the equation: the mattress or the pebbles? Identity politics have become very much a dominant theme in left-leaning politics as of late, much to the delight of alt-Right strategists like Steve Bannon who see the durability of socio-economic class as an organising principle for political action and who see the Left’s emphasis on pebbles of identity unrelated to production as the basis for political organising as a guarantee of failure.
Their belief, one that I concur with, is that emphasising identity over socio-economic class leads to a fragmentation of political action to the detriment of unity of purpose. Horizontal solidarity lines based on objective relationship to the means of production (say, as wage earners) are superseded by vertical silos of self-identification (say, as anime or steam punk fans), something that makes effective collective action of any sort very difficult at best when dominant class adversaries are united.
When identity tribalism triumphs over the class line, the Left is atomised and partitioned rather than consolidated.
This does not deny the fact that there are many for whom the socioeconomic class mattress is very thin and for whom the pebbles of non-class identity loom large underneath their notions of individual and collective self. These people emphasise identity as the locus of political action in capitalist societies precisely because the traditional social mattress of capitalism is threadbare and worn, thereby requiring a more granular understanding of the social relations of factors outside of production.  Adding these into the analytic mix helps supplement class analysis and in doing so paints a more representative picture of contemporary capitalism that helps inform  a more responsive form of praxis that is better in step with the tenor of the times.
It is left for readers to decide which approach is best suited to understanding contemporary capitalism. I for one continue to rest easy on the mattress made of the class-based social relations of production. Beyond that my interest in pebbles of identity derives from the explanatory weight I put on different attributes of the society where I have analytically chosen to place my pillow.
“When identity tribalism triumphs over the class line, the Left is partitioned rather than consolidated.”
More than that, in the USA we are witnessing the abandonment of the Democratic Party by white voters as identity politics over runs that organisation, driving them into the Trump camp. Even American blacks are showing fast growing support for Trump nationalism.
Just as the GOP is in the process of being purged of neocon type paid servants of Globalism, who are either pivoting to Trump nationalism, quitting, or facing oblivion at the mid terms if they continue to run anti nationalist campaigns.
Maybe Identity Politics can take the blame for the Left’s failure to seize the opportunity to put forward a warrior leader capable of delivering the final death blows to an already seriously wounded Globalist kraken.
Right wing nationalism in the form of Trump has taken that opportunity instead.