Ultimate Altima

It's 2003. The US auto industry has been fighting the Japanese for at least 20 years and it's still not caught up to them. This is from a story in the NY Times:
Nissan's Altima sedan, made at its plant in Smyrna, Tenn., was the most efficiently assembled vehicle in North America, requiring 15.74 labor hours. Two G.M. plants at Oshawa, Ontario, trailed the Altima production line at Smyrna: The plant that makes the Chevrolet Impala and Monte Carlo required 16.4 hours. The plant that produces the Buick Regal required 17.1 hours.
If it only takes 15.74 hours to build an Altima, why do they cost $23,689?