Zelda will make insane numbers lifetime. It will do well till the Switch dies.
It will easily surpass 10 million in less than 2 years. It will get some bumps once new Zelda games come out.
Anyway, just really glad Zelda is doing so well and its not only a good sign for the franchise but for every core Nintendo franchise. I think Nintendi doesn't have to fear using new ideas and new franchises anymore with how easily they can market a game on Switch.
I think we will see more bold moves from them during Switch lifetime. Like even Arms is passed 1.5 millions by now this is maybe little compare to juggernauts but for a new fighting franchise with new gameplay, that's huge.
Its showing good news for Metroid Prime 4 and Bayo 3 and hopefully more hardcore and mature games like this. Would love to have a more dark atmosphere Zelda game for the next one.