I think the Tamagotchi brand will live on for a long time at least. Its selling too well to stop it right now. If people lose interest in the toys and they aren't selling well they will come out with something else using the Tamagotchi brand is what I mean. The toys won't stop unless they stop selling, when Bandai starts to lose money on them they will stop making them. Look at how long Nintendo has been making Pokemon games, and yet they keep selling, and are still selling like hotcakes, they aren't going to discontinue making Pokemon games, because if they did, Nintendo would lose a lot of money. If this happens then they might have to come out with some other high tech toy using the Tamagotchi brand to keep up with the changing times and devices. They might even come out with a program for a cellphone, ipod or handheld game system that lets you raise a Tamagotchi! The Tamagotchi brand has been around for years and years and as long as they can keep up with the times and changing technology it should live on.
I think they should come out with a tama that uses normal AAA batteries and has a color backlit LCD like a cell phone or Nintendo DS.