[Someone]

I think basic demographics is a large part of it.

Population of Germany:

  - 1940: 70 million
  - 2020: 83 million (about 20% more)

Population of the USA:

  - 1940: 132 million
  - 2020: 331 million (about 140% more)

Population of the world:

  - 1940: 2300 million
  - 2020: 7795 million (about 240% more)

So, they may have stayed equally innovative per capita, but in 1940 about 1:33 of humans were German, while in 2020, that was 1:94.

[carlmr]

Also maybe losing all scientists to America and half of the country to Russia for 30 years might have contributed here.

A cultural aspect may be that Americans are more willing to try and fail, which in software has almost zero cost. In engineering it's an advantage to be risk-averse. In software where "building" is automated, and barely a factor. Theory almost equals practice here. So it's cheaper to practice.