My guess is it took a couple of losing years to get through the defections from the FBS-to-FCS transition. Now they have a recruiting advantage over other Big Sky teams with their "FBS level" facilities. (plus, its probably even easier to get a guy into Idaho than it is Sac!) Just my hunch.
New Head Coach Eck brought a number of transfer players to the program, as well as a winning mentality having previously coached at South Dakota State, where he served as offensive coordinator.
In general, the facilities at the University of Idaho are third rate at best. However, the new basketball facility is reasonably nice. https://govandals.com/facilities The Kibbie Dome is a dump.
The State of Idaho's land-grant institution has 11k students that have absolutely nothing to do other than go to parties. There is nothing in Moscow. I would pick a university like Sacramento State over the U. of Idaho in a second. Sacramento has a pretty decent night-life with lots of people.