I think the last 20 years of that 45 year period were substantially due to exactly what they described.
If you give any debit for the decade-long Great Depression, or wartime malaise due to loss of life, emotional toll, and rationing, it’s fair to conclude that half of the period of good times was during exactly that post-war rebuilding (largely powered by US industrial capacity) and concomitant baby boom.
There was not any particular discontinuity in GDP per capita growth during the post WWII period compared to previous periods: https://conversableeconomist.com/2023/09/14/the-remarkable-s....