I liked Dragonball the best because the plot started to sputter out during Dragonball Z. I mean the same thing kept happening over and over. They would all be in trouble and suddenly someone (usually Goku) would manage to reach the next level and boom, they've won.
They will probably end when the people who draw them die of old age and they can't find anyone else willing to do it. It's not like they need anyone to come up with storylines. Afterall there's no plot.
Pokemon is the worst anime on the face of the earth. The plot is the same in every single episode! I think they don't even pay people to come up with a storyline anymore. The artists are just trained to draw the same thing over and over.