Some good news, G-Mode is archiving mobile games from the early 2000's and releasing them on the Japanese Nintendo eShop so they won't become lost to time! So far, they've announced four games they're preserving, but here's hoping they'll archive as many as they can! You can read more about it here.
This is an interesting concept in terms of the mainstream gaming community, but it should still be a priority of this community and others like it to to dump the games as originally produced (which, I acknowledge, would be incredibly difficult). You also have to wonder how long this line will last and how many titles will be released in the end.
It would be nice, however, if other developers were willing to do the same thing. G-Mode is hardly the only Japanese company to make mobile games that are no longer available.