It's why Bentley is owned by VW, Rolls Royce is owned by BMW, and the plague of ever-present Maseratis in Southern California are made and leased by Stellantis which also continues to make the world's most weirdly innovative luxury Citroëns.
Pierre-Jules Boulanger who was the CEO of Citroën from 1938 to 1950 produced the Citroën military truck for the Nazis with the oil level indication on the dipstick marked in the wrong place so the engines would seize fairly early in the truck's lifespan. Such a tiny little change in production. The Gestapo couldn't prove anything but they designated him as one of the first people to be arrested and shot in the event of an allied invasion of France. https://citroenvie.com/pierre-jules-boulangers-stele/