We have to zoom out. Indiana is, culturally, a huge sports school. There is more buy-in from the admin, alumns, etc. Even if they have not won big in NCAAB recently, their past success has helped instill that into IU sports culture. Indianapolis and the surrounding regions love football and love HS football. They have notable alumni who are willing to throw money at the program.
Cignetti was the home run hire of home run hires. He's like prime NDSU Craig Bohl on steroids. He knows exactly how to build a winning program down to a science. Indiana plays disciplined, clean, tough, and together in ways I haven't seen since prime Saban Bama Death Star years. He brought all of his good JMU kids with him (under-recruited or transfers from bigger schools) who knew the system so he could go 0-100 right away last year. Indiana is also close enough to recruiting hotbeds to absorb talent easier than Iowa State or Minnesota.
Basically, they had a once in a lifetime coaching hire, pre-existing sports-obsessed school/state culture, and donors waiting in the woodwork to pounce on an opportunity like this. They really hit the holy trinity of program turn-arounds.