No, it doesn't make sense, because the docked mode supposedly upclocks the GPU to 2.5x the speed of the handheld mode. That should be more than enough to run games at 1080p instead of 720p (1080p equals 2.25x as many pixels to shade every frame), and yet this game struggles to even do 900p (which is only 1.56x720p). There's clearly some other bottleneck here, probably related to memory bandwidth. Which does not bode well at all for the future of this console if you hoped it would do 1080p in TV mode in many games. Seems like it will not.
Right, the memory bandwidth is what I fear could be the issue here. We know from the images of the deconstructed Switch that the RAM modules used have an inherent bandwidth of 25.6 GB/s, which is quite limited for modern games. Obviously Nintendo has a history of adding additional bandwidth solutions to the hardware, but this issue could suggest that they have not gone far enough with the modifications in that regard. Evidence for the separate optimisation is Splatoon 2, since it ran in 720p in both docked and undocked mode at the Switch Events.
Alternatively, of course, we are oversimplifying the process of developing for the two different modes (i.e. you can't just make it output at 1080p when it is 720p without optimisation due to different components than the GPU needing better optimisation for that) and Nintendo didn't spend enough time optimising the docked mode (which, in itself, is in contrast to the typical MO of Nintendo, since they are known for good optimisation).
The Digital Foundry analysis that will come down the road could give some clarity, since a third option is that the docked mode has a barrage of extra and enhanced effects enabled that make the game more taxing.
A curious case indeed...
I think the thing that makes the Switch special in this regard is that it improves performance significantly when docked.If the Switch is considered both a home console and a portable, would that mean that the PSP-2000/3000 is also a home console and a portable since it had component out?
I mean, what does it really matter? There have been official ways to play portable games on TVs since the Super Game Boy.