Marxists constantly preach the need for working-class parties and the proposition makes sense, but their failure to create such entities has been a singular failure, an almost total failure. Part of the problem is that while in the era of Marx the proletarian focus made eminent sense and produced a tremendous surge up through the Second International at its start, but then became a problematical set of ambiguities if not contradictions. The discussion must distinguish US, European, and global varieties, and has a long discussion. But even despite that, there is something awry in the various platforms, all by and large variants of Marxist concepts/boilerplate and the mantra of the 'working-class'. Recently, a surge in labor activity, strikes has graced the American neoliberal wasteland for the left. But can the old-style left make any sense of this? In reality the Marxist theory of the working class was somehow flawed. Workers are to lead a revolution and create a working-class state. The only time anything like this happened was in Russia which indeed had a considerable spectrum of working-class soviets. But what was the result? A Marxist bourgeoisie creating a new class state with monopoly control of capital in its new life under Marxist cadres, the working class cashiered and unable to even form unions, all in the name of the 'dictatorship of the proletariat'.
The working class seems to be the only group able to take care of itself. The various leftist groups are really middle-class formations unable to communicate with the working class, or what is left of it in the US. Why not just recognize the reality? In any case, the theory of history as class struggle doesn't quite work: the reality is that middle-class idealists fantasize a working revolution and a state form based on that. What about all the other classes? This meme seems to suggest no one will have any place in a socialist transformation and are wary of the Stalinist implications of the slogans directed against them. Not a very practical way to energize a mass movement.
Again, we should note that a general platform would be based on the Universal Class (with its useful pun on set theory: the Universal class and its subsets of all classes, including the unit class for each individual as a singleeton subset).
Another issue is the defining character of the working-class: if it includes the subset of wage laborers then that is almost everybody. Can one hope that such groups are less worthy than industrial working-class laborers. The whole scheme doesn't make sense.
Why not base socialism on the 'Universal Class' as the destination of all subset classes in the motion of culture toward greater inequality? The working class includes all classes of wage-workers at any level, all subject/object to capitalist domination. In this context, an outreach can be envisioned for all the major subsets of the Universal class. e.g. women, feminism, race, black lives matter, unionized labor, etc... The outreach to the (industrial) working-class would be of especial interest and carry the legacy of working-class struggles with ease. And yet this would be a far more generalized form of class struggle, class action, and would apply to all including capitalist managers in large businesses who are thus wage-laborers.
The working-class revolution made sense in the early era of the industrial proletariat defined as those who much work under duress in dismal factory systems or starve. The work of Marx has been a strange success to the degree that such situations would no longer be tolerated even by capitalists, at least those with hefty PR systems, the case of global sweatshops reverting back to 'original definitions'. Indeed the Universal Class includes the whole global differentiation of 'classes' and the larger global context still asks for the original terminology. The point is that in the US focus on the working class is misleading all parties to think in a wrong way about a situation that is very far from the early industrial revolution. A party envisioned can certainly expect to perform outreach to the working-class, but in the end its focus is a constitutional goal of a mew socialism based on principles that apply to members who joint a group/party.

Source:  Working class, Universal class – 1848+: The End(s) of History