You make some very good points, especially about the shortage of elite teams opening up Final Four possibilities for other teams. And it will be interesting to see how this year plays out given those possibilities. But the argument that this time is different, whether it's about the stock market or sports, makes me skeptical.
In the last 5 years, the lowest ranked defensive team (Oregon 2019) to make the Final Four had the 11th ranked defense by Her Hoop Stats (HHS), and Oregon had the benefit of playing 4 games in Oregon en route to the Final Four. The other 19 teams to make the Final Four the last 5 years all had top 10 defenses. When Arizona "surprised" in 2021 as a non-elite team to make the Final Four, Arizona did so as the # 5 HHS defensive team.
If one or more non-Elite teams makes the Final Four this year, my guess is that the non-Elite teams will look a lot more like Arizona in 2021 in terms of defensive rating than this year's Iowa, with its current # 42 HHS defensive ranking. With Iowa's upcoming schedule, that ranking also seems likely to get at least a little worse. Still, I can pull for Iowa and hope that Caitlin Clark can somehow mimic Kelsey Plum in 2016, who led the one team to make the Final Four since 2010 (out of 96) that sort of looks like Iowa from a statistical perspective.