I never said Brenner had no data to back up his claims. The problem is that since then there has been twice as much data produced by others to dispute his claims.
@ Matthias:
Arrighi uses a total of three historical examples to then project that into the future and claim that this is what is going to happen. It is ahistorical to make a claim about the future based purely on past experience. As you yourself claim, the current situation is quite different from that of the Italian city-states era.
Chris Rude has written about the functional role of financial crises for capital in neoliberalism in a couple of Socialist Register issues.
And of course, Panitch and Gindin, and Panitch and Konings also make a strong case for this. There are others too. You might also want to examine Marx's view of the role of crises for capital also.