GM, its the biggest company that had all the money in the world to be leaders and innovators, instead of building better and more efficient cars, hybrids, they abandoned the small car market and pushed dead end Hummers and Escalades. Virtually all their small sedans are re badged imports.
Take a look at some of the reliability charts, GM at the very bottom, of the big 3 Ford fares the best but its still well behind Honda and Toyota.
The interesting chart is the one showing percentage of worse than average cars that GM makes is actually increasing. As time goes on other manufactures are improving their quality at a faster rate than GM.