In a couple years there will be a new iteration of the Switch. A little smaller and a little cheaper. It won't have detachable joycons, and will be strictly portable, you won't be able to hook it up to the TV. LAN multiplayer would still be available It will be the 2DS of the Switch.
With smaller dimensions, it will either have a footprint like the 2ds or a clamshell/slider design akin to the 3DS and vita go, respectively.
But you say this would totally defeat the purpose of the Switch!!' And I would say, just look at the 2DS. The made a cheaper alternative, killing the 3D aspect, making it arguably more durable, making it perfect for little kids. The same would apply to the switch mini which would have non detachable controllers so they won't get lost.