funnily enough, that is exactly what capitalism postulates.

Well yes and no. I guess it comes down to how you define participation in society. Capitalism only accepts production of commodities, whereas I meant it in a more broad sense. E.g. non-monetized hobbies are classified as entirely consumptive behaviors by capitalist societies, but if you look at the benefits conveyed by an open-source, volunteer project like lemmy you quickly see how much of a misclassification that is.

Even not in the extreme there are broad misclassifications under capitalism. You bring up the example of those of us on welfare; capitalists might agree with you that they are non-participants, whereas I don’t think it’s illogical to claim that services like raising children or advocating for change or community-building or maintaining a home or even just providing emotional support are ways that people contribute to and participate in society. I’d even go so far as to boldly claim that welfare is simply the way the bourgeois convey wages to such people, and then they have the gall to propagandize it as charity to make themselves look better, while simultaneously vilifying this subset of the working class