I'm totally agnostic when it comes to Brenner's argument; its fascinating and, it would seem, a great stimulus for debate, but I'm no "disciple". In saying that I think that you may be painting an over-simplistic view of the structure of Brenner's argument. It seems to me that you've constructed a "causal chain" where there is, in fact, none. Brenner's argument seems to be more (dialectally?) interrelated than the 1, 2, 3, 4 process you put forward above.
As far as I can see his argument begins with the empirical historical claim that there was a crisis of profitability which began between 1965 and 1973. He then claims that the capitalist class responded in the following manner:
"[F]irms, assisted by governments, throughout the advanced capitalist world engaged in an ever more self-conscious, systematic, and all-encompassing effort to restore their profit rates by means both of the obsessive reduction of costs, above all direct and indirect labour costs, and the transformation of their ways of doing business. They detonated an ever more vicious assault on the organizations of the working-class, so as to force down the growth and, in some cases, the level of compensation and social services. They sought to neoliberalize the global economy by deregulating commodity and labour markets, privatizing state enterprises, and freeing up the formerly repressed financial sector, while seeking to force open markets for commodities, foreign direct investment, financial services, and short-term capital throughout the less developed countries. They shifted capital out of high-cost, low-profit manufacturing lines, especially into the financial services and increasingly turned toward speculation. They stepped up foreign direct investment for the purpose of relocating manufacturing in selected regions of what had been the Third World in order to combine low-cost but increasingly skilled and well-educated labour with the best possible techniques, while meanwhile seeking to profit throughout much of the global South by means of the rapid inflow and outflow of hot money to and from the newly freed-up markets in financial assets." (Brenner. "The Economics of Global Turbulence", p. XXII).
As you can see his argument doesn't just swing around a profit-wage axis, in fact he explicitly dismisses this as the main determinate factor in the long downturn in his "Supply-Side Critique" section, albeit from a different "direction", but for similar reasons that he could dismiss the data put forward above.
"Because supply-side theorists (read: wage-squeeze theorists) explain the long downturn in terms of the operations of institutions and impact of policies, they are obliged to explain it in HISTORICALLY AND NATIONALLY SPECIFIC TERMS" (ibid. p. 24 - my emph.).
Brenner, as far as I can see believes that capital can, in the current geopolitical climate AND the geopolitical climate leading up to the downturn, always manage to outmaneuver labour on an international scale (perhaps this is one reason why his argument gets so much hostility from his colleagues on the left?). When the wage-squeeze thesis is posited it doesn't take into account tendencies of international wages, only those that are "historically or nationally specific". The causal chain you put forward above seems to rely on a similar (reductionist?) rationale.
So, instead he takes a single historical claim and then tries to form an integrative picture of the responses by the capitalist class. So when you say that taking into account the redistribution of wages rather than their outright suppression would call into question his whole argument, I don't think it would.
First of all, the suppression of wages is only a part of his argument, a symptom of or response to the crisis of profitability if you like. He also takes into account many other factors; including the growth of finance and speculation, but these are all seen as either symptoms or responses. Primacy seems to be accorded only to the general tendency for overcapacity/overproduction and the inability for "flabby" firms to move out of their lines of production. THIS is the only constant running throughout the work. Everything else attempts to be empirical/historical.
Secondly, and I'm kind of repeating myself, but, no harm, I'm assuming that the stats you put forward above are only those of US wages versus profits. But Brenner, as I claim above, clearly points out that a major feature of the capitalist response was to "step up foreign direct investment for the purpose of relocating manufacturing in selected regions of what had been the Third World in order to combine low-cost but increasingly skilled and well-educated labour with the best possible techniques". Brenner's analysis tries to be global in scope, rather than simply taking into account economic relations within the US. Again, this aspect is absolutely central to his argument. Hence the: "[F]irms, assisted by governments, throughout the advanced capitalist world engaged in an ever more self-conscious, systematic, and all-encompassing effort to restore their profit rates by.....".