Seemingly from out of nowhere, Asian brands came to the American market. They started out laughably underpowered and rust-prone; then became reliable and efficient; then became fast, as well. They originally sold at a premium, because they were scarce and unique in their efficiency. Now they sell at a premium because of their reputation for quality, and almost equal the number of American cars sold in the US.
As the Japanese companies moved upscale, Korean automakers happily filled the gap at the bottom, starting with the Pontiac LeMans (Daewoo), Ford Aspire (Kia), and Mitsubishi-designed Hyundai Excel. Now, Hyundai and Kia offer similar vehicles with excellent warranties, while Daewoo has been acquired by General Motors. Hyundai has been popping up at the top of quality surveys, though Kia still stays at the bottom.