[qwertyuiop924]

>Their mobile products are, in essence, "me-too" products that are larger and less powerful than a smartphone

What? If anything, Smartphones are the "me-too" products. The Gameboy came out in 1989, and the DS came out in the early 2000s, when nobody outside Japan could envision something like a smartphone, and even they didn't have something really usable for the kind of complex games that both platforms offered.

I do agree that they succeed because they have an interface well-tuned to their task. Another reason for success, though, is battery life: When the GameBoy came out, it was really the only portable game console that could last more than four hours. And my GBA (not an SP, notably), a console that has a lower battery life than the GB or GBC that came before it, can last through me playing on it for an entire day, nonstop. Can your phone do the same?

Mind, this is less of a selling point nowadays: it seems even Nintendo's forgotten how to make products with a good battery life.