Personally, I don't buy the idea that capitalism is a self-contained, internally coherent "system." Perhaps that's what it aspires to be, but that's not what it actually is. I am more in line with Deleuze & Guattari's thinking on this matter, who argued that capitalism functions by continually breaking down and thereby expanding its own limits. For D&G, capitalism is constantly undergoing a schizophrenic oscillation between deterritorialization and reterritorialization. As they put it in Anti-Oedipus,
Hence one can say that schizophrenia is the exterior limit of capitalism itself or the conclusion of its deepest tendency, but that capitalism only functions on condition that it inhibit this tendency, or that it push back or displace this limit, by substituting for it its own immanent relative limits, which it continually reproduces on a widened scale. It axiomatizes with one hand what it decodes with the other. [...] And it is impossible in such a regime to distinguish, even in two phases, between decoding and the axiomatization that comes to replace the vanished codes. The flows are decoded and axiomatized by capitalism at the same time. (246)
My objection to the term "The System" is not that it is too broad, but precisely the opposite: it's far too specific. It implies something that is localizable and clearly demarcated, something that someone can point to and say "that Thing over there that we are against." The reality is that the boundaries of capitalism are constantly dissolving and being rebuilt. The question that anarchists should be asking about capitalism is not, as Deleuze would say, "what is it," but "how does it work?" While speaking of capitalism as a "system" may be useful for ease of communication within the common vernacular, it also has a tendency to obscure how capitalism actually functions.