Several billion dollars isn't really that much money in consumer terms. American consumers spend something like a billion dollars on scented candles each year.

Besides, it doesn't seem to me like there was much of a delay at all in getting generic loratadine to consumers:

http://www.nj.com/news/stories/0827_claritin.html

The patent expired in December 2002 and Geneva/Novartis had first-challenger exclusivity for 6 months. By August 2003, only a month or so later, the lawsuit was decided and the floodgates opened.