Its a combo of having strong enough hardware, talented team and giving them enough money and devtime, flagship switchgames, that sell like hotcakes and get much love, so both zeldas, had everything in the equation but strong enough hardware, so they looked worse from AA ps4 games and still dipped below 30 at nasty low resollution, some things cant be made on some hardware, compromisses had to be made.
Now we getting rumors about next switch being roughly on pair with ps4 undocked and ps4pr0 docked, coming next year, so nintendo fans best case scenario will be roughly(or even below) xss lvl when docked, and we all remember well how any demanding game(or matrix demo;p) runs/looks on xss