War does not end depressions, the death of FDR and his economic policies with him ended the depression
The fact that the Depression dragged on for years convinced generations of economists and policy-makers that capitalism could not be trusted to recover from depressions and that significant government intervention was required to achieve good outcomes,” Cole said. “Ironically, our work shows that the recovery would have been very rapid had the government not intervened.” http://newsroom.ucla.edu/portal/ucla/FDR-s-Policies-Prolonged-Depression-5409.aspx
I’m not so sure those policies died with FDR.