It's definitely possible. I mean, the appeal is there. Just depends on Nintendo. If they release a mini and XL versions it'll probably happen, we already have 2 in the household because they're right.
It is going to sell like a handheld, but it's going to sell like a handheld+ because hooking it up to the TV is easy and works well. A lot of the games look surprisingly good on a big 1080p TV (sorry people, most of us do not have 4k TVs and probably won't for 2-3 years).
But it is also just not as portable as the 3ds, you can't just slip it into your back pocket so I feel it really won't tap into that market until they have a mini version. Clamshell design where the removable mini joy-cona slide into the top cover so when closing it's just like a 3DS. Still works wirelessly with all Joy-Cons.
Also, they still need apps, but I kinda feel like that might be a bigger hit on the XL version. As of now it's a games only machine, but if you wanna hit that mass market having Netflix and Hulu and other apps would broaden it's appeal as a tablet like device.
I can see this thing selling for years if they price it right. Hopefully they don't get greedy, I wouldn't launch the mini or an XL for 2 years. At that time, drop the price. Mini for $200, standard for $250 w/ a game, XL for $300. But the XL should be BIG, like a 10 - 12 inch screen.