Another argument against the autonomy of central banks is that they form part of overall economic policy and that there can be no meaningful separation between fiscal policy, monetary policy, labour policy, trade policy or for that matter any other policy measures.
We have some evidence from recent years that all or most of the decline in the saving rate is accounted for by the upper income quintile where the capital gains have disproportionately accrued, which suggests that the wealth effect has been real and significant.