A retrospective feature for an ex-Danger employee reveals that Nintendo once dabbled in bringing Game Boy games to mobiles.
Danger, a former hardware company that designed one of the early smartphones - Sidekick - once developed an internet-based distribution system for playing classic Game Boy titles on the phone. Playing retro gems unofficially on smartphones and tablets is nothing new in this day and age due to the rise of emulator software on market, however it was an idea that Nintendo had once tinkered with alongside Danger.
Describing the process in a blog feature, Chris Salvo noted how "executives at Nintendo were blown away" at the concept, which involved an app that would distribute Game Boy ROMS over the internet through an app store feature. "Pick one, buy it, download it, and be playing it in seconds with no need to haul cartridges around with you" was the core objective, with the games automatically pausing when receiving a phone-call.

However, despite the keen interest from Nintendo, the "license for all of the games in their catalog didn't include rights for electronic distribution" at that point. Deadlines were looming and "there was just no way we could have gotten a big enough catalog of titles built up in time for Christmas that year."
Inevitably the project came to a halt and likely was fed into the early concepts of the Virtual Console on Wii several years later.
Do you think Nintendo should have released Gameboy games back in 2004 on early smartphones?