Just because there are 50 million 3DS' sold doesn't mean there are 50 million active 3DS owners.
A lot of kids that got a 3DS in 2011 or 2012 may look at it as antiquated and old hat now that it's 2015 and they have say their first iPhone or iPad.
Everything about it just screams "dated", probably why Nintendo desperately tacked on the "New" moniker to the latest 3DS revision -- as a brand it's losing juice and they know it.
Also in this day and age, convincing people to pay $40 for a handheld game with PS2-ish graphics on a terribly low resolution/muddy looking display is a tough sell to the "I'm used to my Retina resolution screen and can get games for free or a $1" crowd.
Nintendo needs to bring something to market that isn't seen as being outdated or stuck in the past decade.









