Yep. Pokemon stormed the American airwaves in 1998-1999.
In 1999-2000, Fox Kids rushed to cram Digimon, Flint the Time Detective, and Monster Rancher into their lineup.
In 2000-2001, they dropped Monster Rancher and added Escaflowne.
In 2001-2002, they dropped Flint and Escaflowne, and picked up Medabots, Mon Colle Knights, and one season of Transformers Anime.
They were definitely reacting to Pokemon. But it's not like they were the only ones. 2000 is when Cartoon Network jumped from having Robotech, Sailor Moon, and DBZ, into a real massive tsunami of anime programming. Nelvana tried to follow Pokemon in the syndication market (basically free-agent TV shows that haven't signed with any network) with "Cardcaptors" in 2000.