I honestly don't think it'll ever be as big as before, unfortunately. There was certainly a time when it was beyond popular in the US, but that was before the onset of iPads, smart phones, and highly advanced game consoles. Japan can get away with it because of their culture and lifestyle; the population density is higher, and public transportation is much more common. There's a far bigger chance of running into someone who has another Tamagotchi, so it makes it more accessible (and fun) then it would be here. You can bump into a random stranger with a Tama on the subway, connect with them, and be done a minute later. It's the same reason handheld gaming is so much more successful in Japan. It's just a different culture.
That being said, I still think it would be possible if Bandai advertised Tamagotchis once again in the US. There was that short popularity spike back in 2004 when they actually put effort into it, after all. They haven't bothered advertising much since then, which really is a pity. Tamagotchis will most likely never be as popular here as in Japan due to the culture difference again, but that doesn't mean they can't be a well-known, wanted toy like they once were if they went about it the right away. The Tamago wasn't the right way at all. Don't get me wrong, I enjoyed it quite a bit, but most kids today would see it as completely out-dated. On the other hand, I could see kids begging their parents for an ID L if it was released here with a decreased price tag (products are usually more expensive in Japan then the US anyway). Bandai America has to catch up with the times and what's in demand. Color toys with tons of options and interactivity are it. 8-bit or grayscale that haven't changed much from the originals...that's not going to cut it.
So, in short: It'll likely never reach the peak it was once at, but it could do well if Bandai actually tried. No offense to Bandai America, but they could do better.
