Passive solar design is about creating a home which needs little energy to stay at a comfortable temperature. It's unrelated to generating electricity via solar power panels.

The northwest US doesn't seem* to be worse than most of the Europe, where we have a veritable boom of solar power. Granted, it produces next to nothing during the winter, but the yearly production makes it profitable still. Even for well insulated house you need some heating in the north, but it can be surprisingly little. It's not like these houses are going to be built totally without network mains.

*: https://globalsolaratlas.info/

Solar is more effective in low temperatures than in high temperatures. Also northwest US is max around 49 degrees north, which is around Paris in Europe and it is normal to have solar much farther north in Europe