To keep its North American profit machine revved up, GM will have to invest in new SUVs and trucks, as well as expensive technology to enable those trucks to meet rising federal fuel economy targets.
Europe is demanding cleaner cars, too. But far less of the technology GM would buy to clean up European diesels and tiny gasoline engines would be useful in the U.S., where larger gasoline engines, including eight-cylinder motors used in pickup trucks, dominate the market.
GM has concluded that it cannot achieve significant economies of scale in emissions technology for Europe on its own, company executives said. Peugeot CEO Carlos Tavares is wagering that he now can gain an advantage against rivals such as Renault SA and Volkswagen AG with the help of the added revenue and sales volume provided by Opel.
France's PSA Group, the maker of Peugeot, Citroen and DS cars, announced a deal to buy GM's Opel division on Monday.
GM's decision to walk away from Western Europe highlights two other profound shifts since 2009, when GM's board scuttled a deal to sell Opel and Vauxhall to a group led by auto supplier Magna International and Russia's Sberbank.
The first is China, now the world's largest auto market with roughly 28 million vehicles sold in 2016, and more growth forecast to come.
As China grows, GM will need to shift more vehicle engineering money and capital investment to feed that market -- which could eventually replace much of the global sales volume sacrificed by the sale of Opel to Peugeot SA.
GM's Buick brand, its primary brand in China, and the Wuling brand of small commercial vehicles GM builds with partner Shanghai Automotive Industry Corp., each outsold Opel and Vauxhall in 2016.