I just want to point out that Zelda is no longer the only big game of the Switch.It was during March and April, but at this point we also have Mario Kart, ARMS and Splatoon 2(its close enough to claim this), so your point is half right.
But yeah, Zelda sales are incredibles.
My (locked) thread about how difficulty should be a decision for the developers, not the gamers.
https://gamrconnect.vgchartz.com/thread.php?id=241866&page=1