I think there is more into Brenner's argument than you attribute to it. First, he does not show just correlation but a mechanism (international competition) and timing sequence, which typically suffices to establish causation. Second, he does not limit his argument to US and EU, but also includes Asia (especially Japan.) Third, he specifically argues that investment led to increased productivity (especially in Japan) so the critique that he sees financialization as invariably parasitic does not quite stick.
Of course, one can can argue his specific empirical points (e.g. the selection of timing) but that does not mean that his main argument - that the emergence of new developmental states willing to invest heavily in increasing their productive potential puts downward pressure on prices which in turn undercuts profit rates in established industrial nations - is without merits. One can argue whether this is a fatal flaw of a mere hiccup - but that is fundamentally an argument about the future not the past that Brenner makes.
Wojtek