One metric defines what I believe is the greatest human achievement over the last 75 years; an increased human lifespan.
In 1943 and in the U.S., the average lifespan was around 63 years. (Life expectancy in the USA, 1900-98) As of early 2018 the average US life expectancy is projected to be an average of 78.7 years, mostly due to medical advances (especially infant-through-teen health), healthier heating systems, proliferation of air conditioners, safer work and home conditions, transportation safety improvements and disaster response systems. A 16 year improvement over 75 years time is pretty astonishing, although the last two years shows America slipping backwards for a number of reasons.
Of course, an increasing lifespan along with increasing child births, resulting in a population explosion, is stressing both our habitat and our economy.