The problem is that sometimes it passes (from some Keynesians that I read) that proper economic policy would be enough to maintain the status quo lifestyle. That state anti-cyclical intervention (and redistributive policies) would be enough to counter nature's limits. Indeed many of those keynesians ignore nature's limits (hence my comment on post-industrialism) and clearly talk about growth (in very real terms).

Any realistic politics for the future will have to consider a shrinkage of the resource base. That, by the way is more encouraging of redistributive policies: "trickle down" would only make sense in a infinite growth (real) scenario: If there are limits then if some get more and more that can only mean that others get less and less.