I'm a bit of a skeptic about the reported ISU WBB attendance figures, but would defer to the ISU fans on here who know more than I do. To an outsider, between various kids' days and other promotions, it seems like ISU gins up or inflates their numbers. But you can't do that in the NCAA Tourney, when the ISU numbers drop precipitously.
Two years ago when ISU hosted in the NCAA Tourney, their second round game against Georgia reported attendance of 6,283. Their first round game that year had 5,546. In 2019, when ISU lost at home in the 2nd round of the NCAA Tourney, the reported attendance was 5,809. Seems strange that their home fans disappear for the NCAA Tournament. I get why South Carolina fans might stay away from First and Second Round games, but don't think the same thinking applies to ISU.
In contrast, in 2019, when Iowa hosted, they had 12,376 for their second round game. When Iowa lost at home to Creighton in the 2nd round in 2022, they had 14,382 (the reduced Iowa capacity for an NCAA game). Last year, when Iowa beat Georgia in the 2nd Round, they had 14,382.
I also think that Iowa is guilty of inflating their home attendance numbers this season, in the sense that they are using the paid attendance figures (the season was a sell out), rather than actual butts in seats. Iowa had 2 December home games against lesser competition (Bowling Green and Loyola Chicago), with quite a few open seats.