Mr gimmick like game for the GBA help wanted

[Sketchasaurus]

My main question is this: why waste the time, money, etc. to make a game play on a platform that only a relatively small niche still has?

The amount of time and money that would go into developing a game for a discontinued platform is simply not worth what miniscule payoff that might not even be there.

I'd recommend developing the game with the intent of having as many people able to play it as possible. i.e. Steam/Online/WiiU/PS4/Xbone. While it'd be kind of cool to have a physical cartridge of one's own game, it's a waste of money to mass produce obsolete cartridges