Idaho has been badly in need of a fast north-south highway for 100 years. There's simply no place to put one. It's a narrow strip through canyons with Hells Canyon to the west and high, steep mountains to the east. The 150 miles from Boise to Riggins is impossible. From Riggins to Lewiston is better but still not easy for building a freeway.
Y'all do not need a "fast north-south highway" if you are at all interested in keeping Idaho as Idaho.
