I guess losing nine in a row to FBS opponents, capped off with an embarrassing loss in Corvallis will put you on the hot seat.
That said, while the record was going to get him fired eventually, it wasn't what did him in midseason. Here's the money quote from Arizona AD Greg Byrne at the presser:
We want them to have some fun playing football. We wanted our coaches to have fun coaching.
His antics were clearly hurting the team. I don't wish ill will on Mike Stoops, and hope he learns to be a better coach wherever he lands. But, as we've said repeatedly on our podcasts, his behavior on the sidelines was an embarrassment to his program, the conference, and college football. It wasn't good for the kids playing the game.
I guess you can get away with being a jerk when you win. But to be a jerk AND and a loser just doesn't cut it.
Its already a lost season for Arizona, but it will be really telling if UA rips off a winning streak after this. They certainly have the talent.