Biggest problem is that despite having such a large library of exclusive games that people want is the hardware. Westerners like myself could never imagine that being the most popular console here in America when we can get a pre-built gaming computer, admittedly for a lot more price wise and emulate those games with better performance and still be able to play more games than just those exclusives.
Believe it or not, the majority of people don't just default to "but I could just pirate this instead", especially when a decent computer will easily be more than twice as expensive as a switch.
Beyond that, you lose out on the multi-player aspect of things. The switch is also far better in terms of portability than the alternatives in pc space, both in terms of size and battery life.
the article lists a source. Game Watch. Translated from Japanese to English.
"Cumulative domestic sales of Nintendo's game console "Nintendo Switch" series exceeded 33.34 million units. It exceeded the record for the Nintendo DS series of 32.99 million units, making it the best-selling game console in history in Japan."
This is much easier if you read the article and check the sources yourself.