It mostly worked because in recent history the Germans were an occupied state [0] followed up by a very polite situation that wasn't an occupation but looked a lot like one by the numbers [1]. The US has a number of troops in Germany comparable to the German army. Note from the article that up to 2006 the US had more troops in Germany than the Germans did.

Economic integration wasn't what kept the peace, it was probably the military integration.

[0] https://en.wikipedia.org/wiki/Allied-occupied_Germany

[1] https://www.aljazeera.com/news/2021/9/10/infographic-us-mili...