(Answered by Adam Begun)
In Peter’s own words: “when it’s over, its over”.
Pete didn’t leave with a polite handshake and a “best to you all” attitude. He left with a “thank f*cking God I don’t ever have to do THIS/THAT again” attitude.
As for the R&RHOF: he was approached by the band to sing “25 or 6 to 4” for the group’s performance that evening. The song is in the key of A minor and has been played that way since it’s inception and the horn parts are (virtually) cemented in place in A minor. Pete wanted to change the key to E minor…deliberately…knowing that would be impossible for the horns to cope…and the band said: “no”. Pete shrugged and said: “ok, then…no”. The rest of the group said: “fine, then…it’s a shame, but I guess it’s not to be…”.
(For the record: you can’t “just” transpose a brass section down a fourth without major, MAJOR musical issues.
Pete might as well have said: “I’ll do it if you guys can swim fast in quicksand….no, faster than that…”)
Peter drew up his own terms to play in the R&RHOF induction and chose not to even show up when his “demand” couldn’t be met.
This really does show Cetera’s utter contempt for Chicago and his indifference to his time in the group…
…even if he wouldn’t perform he could have been in the audience cheering on his old group for finally getting the respect that they deserve.
Whatever. It’s (very) over by now and a reunion is completely impossible.

