OR wait until game 9 or 10 of the current season.
In football firing a coach is ending the season. Why would Hobbs do that to the players?
My guess is that it was all about $$$. If boosters/etc were showing the financials rapidly falling off a cliff, and he knew that he couldn't get the BoG to move if Ash managed to eke out a win over Maryland or Indiana, he might have had to go when there was an opportunity.
An October firing isn't unprecedented, though. Here's an article from 2017 outlining 18 other coaches that were fired before November.