Imagine the terrible effects on the economy when tens of thousands of professional trivia players are thrown out of work.
Although, come to think of it, I don't think the rise of computers to the top ranks of chess hurt the chess community at all. Humans just play the game between themselves and ignore the computers, just as we ignore the speed of racing cars when we run Olympic races and ignore the superior mobility of eagles when flying kites.
The future of trivia is not particularly imperiled by Watson. It's imperiled by the fact that we're all starting to carry Wikipedia and Google around 24/7, and therefore the ability to memorize and recall trivial knowledge has about as much relevance to our futures as the ability to turn raw cotton into clothing. It's likely to become a quaint hobby that young people can't understand the point of.