(No, this isn't a post about 3DS sales ending. That hasn't happened yet.)
Ever since the Gameboy, handheld consoles (primarily Nintendos) existed as an alternate (and competent) development avenue for developers, to make games that focus more on story and gameplay rather than pushing graphics (for obvious reasons). These games often required much less money to be spent on development, so smaller studios could shine on those systems as well.
With the 3DS on its way out, there won't be a medium where these games shine as the primary ones. Granted, Indie games do exist, but since they're sold at a fraction of other games on consoles, they won't be viable for big studios to make, and they're rarely going to be on the same scale as what we've seen on handhelds (with exceptions of course, i.e. Shovel Knight). And they'll obviously be outshined by big AAA games on those same systems, with higher expectations from the userbase.
Granted, the 3DS wasn't a system of basic graphics (with some very pretty games like RE: Revelations), but it was still far behind compared to the home consoles. With the Switch being the successor to both the 3DS and WiiU, there won't be a dedicated device for these smaller games, where they stick out and not get outshined by massive studio games.
Thoughts on this subject are appreciated.