The decision of when to fire is basically a $3.3MM decision. The costs for this year are sunk no matter what you do. But the costs for the last 3 seasons on his contract are not.
His last 3 years would be $3.4, $3.5, $3.6 - so $10.5MM. The buyout after the season is $7.2MM ($2.4MM * 3).
For an AA with consistent money issues $3.3MM is going to be hard to swallow. Also, the way the schedule works plays in favor of not firing during the season. 4 of the first 6 games are home games, only 2 of the last 6 are home games and only 1 of the last 5. The season tickets are already payed for. So it is really only the walk-up tickets and any spending that those fans do that is the lost revenue. If you look at how many people are in the stands (not what is announced attendance which is tickets sold) it seems reasonable that the lost revenue of people not buying tickets for an individual game is likely less than $1MM total.
The recruiting class isn't good enough to even worry about in the slightest currently 48th on Rivals and 52nd on 247sports (and 12th in avg rating on both among 14 ACC teams). Also imo decisions on hiring and firing coaches should never be based on recruiting - that is a very short term focus.
The goal if you make a coaching change is to get the best coach for your school that is interested in coming. It's not the biggest name, it's not who may be the 'best' coach out there. It is who amongst the candidates that is interested in coming to the school is most likely to succeed.
I think if GT ends up 1-5 or 1-6 then we might see the AA pull the trigger (Lewis was 1-7 when GT pulled the trigger in a time where buyouts were not a big deal). If he wins even one game of the next 3 I think Collins coaches the season out.