There are numbers from Nintendo on the breakdown between mobile and dock usage, and they indicate a larger percentage of users play undocked vs docked.
I saw the same numbers. They are from 2017 just months after it was released, back before many Nintendo exclusives had been released and even these numbers show 70% of users spend significant amount of time docked.
The numbers are 13 million lite vs 85 million non-lite sales.
The mobile part is a meme, it's subsidized by the people who just want play Nintendo games (and the switch is the only/best way to do it)