Well, definitely you throw out some unpopular opinions mate 😅
I don’t think Nintendo is not good anymore, so many of us think that, and I agree the DS being superior, but the 3DS wasn’t a disappointment, indeed without it maybe Nintendo would have been the new SEGA lol.
The 3D gimmick was just that, a gimmick, nothing revolutionary but at least you could turn it off, and when you were bored turning it on was an option as well, without considering the actual titles that use it very well and you feel comfortable having it always ON with those.