Since we're in the general section, I've decide to give my point of view concerning how long the manga and anime will last.
2 possibilities for the manga :
-Gosho ends the story properly in 5-10 years. Sequels are then published by other writers (it's happened with other franchise like Saint Seiya).
-Gosho dies before finishing the story (it can happen, unfortunately), the manga is then stopped or his assistants take over. Sequels aren't to be excluded either.
Anime-wise, I see the anime going on even after the manga ends (if it does) with AO stories, adaptations of the Special volumes and of the new cases in the sequels. The anime has one very important purpose which is to promote the movie : given how much cash they bring in on an annual basis, there is no way they will stop coming out.