Statcounter attempts to track what was used to visit internet websites. What the stats you picked are showing is not how many consoles are out there, but which consoles are used the most to visit internet websites. Switch doesn't have an internet browser, so that's basically Youtube visits because that's just about all that can be done with Switch.
Ok, thanks for the clarification. I gotta call out CNBC for their misinformation now for using this to act like the Switch's OS market share is much lower than Sony & Microsoft since they were trying to downplay Nintendo's success with the Switch in favor of Apple Arcade & shitty Stadia.