Wow I am pretty surprised no one has tried to take a closer look on how this could be a reasonable prediction. Everyone is citing potential 1st Party games, price drops, and revisions. These measures will certainly help the Switch maintain a steady trajectory, but there are factors that could seriously elevate the system.
1. One of the reasons Sony has been so successful even through its missteps in the PS3 era is due to a more robust world wide market to sell to than either Nintendo or Microsoft. The article hints at the Tencent MOBA revealed in the last direct as a big deal and it is. If Nintendo can step past their normal bounds and break into a gaming market primed to explode like China or even Brazil or India with the Switch it would be tremendous. I'm interested to see if more games geared towards the Chinese market start to pop up or if Nintendo plans to expand distribution in these growth economies.
2. The casual audience is still out there! It is true many have moved on from gaming since the DS and Wii era, but that doesn't mean the Switch can't attract some of that same audience back. Nintendo has been very core focused to start out the Switch, with a bit of eSports pandering on the side. That could change though! I would be surprised if they didn't try something along the lines of a "Switch Sports" title with out of the box 2-player support at the very least. The social aspect of the console is big and can be driving factor if they get more games that take advantage of it.
3. The other big thing I think is going to be an eventual GTA5 port along with stronger 3rd Party support. My gut feeling is that the cold, abused, distrustful (of Nintendo systems) hearts of 3rd Party publishers will start to thaw out over the next year as more success stories come out and the Switch proves to be viable for even non-Nintendo published games. Having a portable option for GTA, Madden, FIFA, COD, Elder Scrolls, Minecraft, and more with multiplayer out of the box and flexibility on how to play will be a big draw. I don't know this for certain, but at the very least it should get every indie release for the foreseeable future.
4. The only other thing that I think could really help them out is unlikely, but who knows. An actual, logical, Virtual Console. Don't trickle out the same releases for the first 6 months have a good majority out at the start, have a viable upgrade path from previous systems, price reasonably, and include GameCube games. The other option would be to make it a Netflix-esque service for access to a large catalog of games.
I think if a combination of all those things happen, to varying degrees, in addition to the expected strong 1st Party support, revisions, and price drops, then Nintendo could get in that range.