I did read something interesting today.
Currently devkitPro is researching the feasibility of a branded flashcard without piracy features which should hopefully preserve our ability to create and share homebrew.
What if they managed to do this, then continued it on with the 3DS? We wouldn't be needing to jailbreak anymore. Or use AP circumvention methods.
That has been on the HB Menu page (I think that's where it is) for as long as the HB Menu page has existed (at least one year, possibly several) and nothing has come of it. There is already at least one homebrew only flashcard (Datel's Games n Music), very few people bought it as I understand because it was more expensive than other cards, so they figured they may as well get a cheaper one, even if they weren't going to use the ROM loading features.
There was also the iPlayer, but some people managed to get ROM's running on it.
The thing is, the moment you allow using unsigned code, there will be piracy. You can stand on your head, there still will be piracy. Someone someday will write something that will allow it, just because. Homebrew-only solutions are fairy tales, a dream never to come true, and maybe that's a good thing.
Everybody should have the right to backup their software, even software sold on cartridges. This obviously leads to even more piracy, since people find ways to boot illegal backups anyways.
All that said, no, a Homebrew-Only solution either won't sell well, since to cripple its backup compatibility you'd have to also cripple features, or it will be hacked itself to play backups. It's a viscious circle.