I really don't think the Switch is going to replace Nintendo's handheld line, it's not nearly as portable
Now people think the Switch's battery life is stuff only because of it's battery life handling BOTW.
BOTW is an open world game, and it's loving huge and detailed.
I understand the whole, 3 hour limit.
On the other hand, the other games I've played so far don't give me this '3 Hour' Limit.
Shovel Knight doesn't do this.
I have a feeling Mario Kart 8 Deluxe won't do it either.
And just to put the final nail into the coffin, The original 3DS claimed it could hold about 7 hours of charge for games on low loads.
Not that much more than 3 hours.
Finally, watch this real time battery test:
https://www.youtube.com/watch?v=T6Rqaf9lMrgThe 3DS only lasted 3 Hours a nd 25 minutes, the 2ds soon after, and the the new 3ds mini died.
Unfortunatly the original 3ds XL wasn't a fair test as it has an extended battery on it.
But the switch beat all the non-modified Nintendo handhelds on the table (sans the original DS) , while they were just on the main menu.