Yes but they'd always done well in the regular car market as well. itd hafta be WAY cheaper than its rivals because noone with lexus money is going to want to save some buying a hyundai.
You are obviously very, very, very young. Toyota and Nissan (and Honda) didn't do very well to begin with, and they were synonymous with "cheap crappy cars that don't last" up until the 70s - and they'd started in the US in the 1950s!
Nissan got their jumpstart in the US with the 240Z, which started changing a lot of minds. They really catapaulted onto the wider US mindshare with the 280ZX and the Corvette-killer 300ZX.
Toyota went the other route - by producing the stupendously cheap 1979 Corolla that just wouldn't die, and the 79-up HiLux pickup truck, which also was cheap and just would not die. Substance over style. Their first *big* US hit was the 1984 Camry.
Honda started in the US in 1953 and didn't get much attention until the 1976 Honda Civic (CVCC) and later Prelude. The first Accord was their first real US hit.
It took the Japanese about *thirty* years to get to the point where they were on par with the US domestics in terms of mindshare and sales. It took them another fifteen years to equal and surpass the likes of BMW and Mercedes with their luxury brands.
It only took the Koreans *ten* years to match the domestics. And, it appears, it's only going to take them another year or so to equal the Europeans in some respects.
Is it any wonder why the Koreans are on *everyone's* minds? They're Japan, Inc.'s biggest worry right now.
The question isn't "Can the Koreans build a luxury brand?" but it's "How long will it take, and will they be able to sustain it?" and "How will the Japanese hold up?"