Your point is totally valid that people should ride what they like and works for them. And I understand that there are more reasons to ride a tandem than just the equalizer effect.

However, given that you say you don’t really want an electric bike, but your wife needs it for the hills in your area and the distance you want to ride, and assuming you already have a single, isn’t the easier answer just to buy an electric bike for her that she rides with you and you on a non assisted bike.