Silent_Buddha
Legend
Wii U counts, there were lots of people having a Wii U but not a 3DS, this counts a lot in the first two years.
Also PS Vita, it sold above 15 millions and many of the people that bought it and never owned a 3DS may be interested in Switch (It's successor for an hardware point of view)
I'm not sure there were ever "lots of people" having a Wii-U considering less than 14 million units sold worldwide. The NSW has over doubled that number sold in less than 2 years.
That said, I'm sure most people that had a Wii-U probably bought a NSW. Hell, everyone that had a Wii-U probably owned a Wii.
The hallmark of a good product is getting your existing customers to buy into a new product that you make as well as enticing people who aren't invested in your products to buy into your products. The NSW has managed to attract and retain people who were previously uninterested in Nintendo products. That isn't to say that most buyers haven't owned a Nintendo system at some point. But that many NSW owners didn't own a 3DS, Wii or Wii-U.
It's always fun to see someone who's last Nintendo console was either an N64 or Super NES, falling in love with the IPs that they loved back when they owned those machines as kids. Or seeing kids discovering Nintendo titles for the first time and going absolutely bonkers.
Regards,
SB