All I can say is, there are dialectics and there are dialectics.
It's not, in any way, a matter of "brushing aside" the Mode of Production, simply pointing out MoP is not _always_ as meaningful as supplementary concepts. For example, Marx pointed this out himself when said that in 19th Century India --- dominated by the British capitalist state and therefore a(n important) part of the emerging world CMP --- the dominant form of surplus extraction was the finance industry (stretching down to village money lenders), exploiting peasants who were involved in subsistence agriculture/petty commodity production. That is to say, although most of the population were still "peasants", that word tells us nothing about the main form of accumulation and its long term effects on the population.
Neither would I ever say that "kin relations" are "already gone" or that the family "has been entirely removed it from economic importance in advanced economies." Those things will probably never happen completely. But I wouldn't like to guess how far production can displace reproduction.
Isn't it "healthy" to be "skeptical" about something that seems (at best) a hypothesis of anthropologists? In terms of history generally and Historical Materialism in particular, I think primitive communism comes up against a brick wall: there is no convincing historical evidence of it as a dominant mode of production (compared to, e.g. "hunting and gathering"), so how can it be considered to have any material relevence? To believe otherwise seems like a conception of praxis simply in terms of the (paradoxical) ontological dogma known as "dialectical materialism", a burden we did inherit from Engels (not Marx) and one which I'm happy to disown completely.
Regards,
Grant.