I'm having trouble parsing your last sentence, 'an opportunity to argue for'? I suspect the rich often got that way by being able to capitalise on crises, but I'm not sure how that relates to arguing for such opportunity. It might be relevant that Picketty also points out how severe crises are about the only times in recent history that wealth inequality decreased.

I generally like Picketty's analysis, but I wonder whether it might be worthwhile to do a similar analysis and include the portion that goes to co-ordination costs. It might be irrelevant in france for cultural reasons but I suspect it's an important piece of the puzzle in the Americas.