While I am not an active Switch developer, I am a programmer, which I why I think it would be fairly trivial for Nintendo to do this. When games switch (no pun intended) to their docked mode, it's really just caused by the USB-C connection inside the dock saying "yes, you are connected to a TV now", which puts the Switch hardware into its higher-clocked modes and tells games to run in their docked graphics configs.
So, again, Nintendo doesn't obviously need a physical USB-C connection and a dock to tell games to use that config. They could just tell them anytime at the OS level.
How efficient is that? And how much would that cost compared to what MVG is saying?