Nintendo offers the "Virtual Console" on the Wii and 3DS.

Unless my knowledge is out of date, Nintendo's business model revolves around licensing for publishing software for their hardware, so it's in Nintendo's best interest to sell hardware, and not to support emulation on other hardware.

On a related note, when Sony sued 'Bleem!', it argued that running the software on other hardware destroyed Sony's control over the player's experience, and as a result hurt their brand.