I think @slice60 said it most eloquently back in April:
”Yes, I can explain it. The IHSAA crapped the bed.
Here is how Chatard has fared in the last 25 years (22 of 25 years in 3A, except where noted). Chatard has won the 3A state title in 13 of 22 tournaments over the past 25 years. If that doesn't scream MOVED UP DUE TO SUCCESS FACTOR, I do not know what does.
99-Lost in Sect (Roncalli-State Champ)
00-Lost in Sect (Heritage Hills-State Champ)
04-Reg Champ (Andrean-State Champ)
05-Reg Champ (NorthWood-State Champ)
08-Reg Champ (Bellmont-State Champ)
09-Reg Champ (West Laf-State Champ)
13-moved up to 4A, won Sect (Andrean-3A State Champ)
14-moved up to 4A, lost in Sect (Tri West-3A State Champ)
16-Lost in Sect (FW Concordia-State Champ)
17-Sect Champ (Ev Memorial-State Champ)
18-Reg Champ (West Laf-State Champ)
21-moved up to 4A, lost in Sect (Gibson So-3A State Champ) "
I think there was a very real concern that Chatard might run into it's second string of three consecutive non-state champ seasons in eight years and the IHSAA wanted to nip it in the bud. The embarrassment that this kind of perceived downturn in a program as storied as Chatard might lead to the utter collapse of the team, the Chatard community, and, more broadly, the entire 3A class. How would the IHSAA move forward with only five classes of postseason football being viable, while 64 3A teams wander aimlessly from one gridiron to another for a month, sometimes three schools on the same field, occasionally a team stumbling into a different state's playoffs entirely. Something like this could ultimately be the downfall of Indiana football as well know it.
Meanwhile, I believe Dwenger and LCC both stayed up this season, if I'm not mistaken.