Based on the UGA folks I interact with, I'd say the Fire Ricth crowd is very vocal but doesn't represent the majority. Most are frustrated with his inability to win "the big one", but they also realize that the downside risk to firing Richt is significant. The worry is that UGA will end up like Michigan - fire a coach who has been a consistent winner and slip into mediocrity for an extended period. Most that I've spoken too would rather take the known (Richt and the 10 wins with occasional title hopes) than suffer through 5-10 years of bad football. Perhaps 92Tide or one of the other Atlanta guys can chime in with their thoughts as well. They may have a differnt view point.
I'll add that for the amount of money they make, UGA has spent very little on football until recently. Unless it become financially untenable (meaning the dollars stop flowing in because the football team is performing poorly), they aren't going to fire Richt. He's only recently surpassed the $4MM mark in pay and hasn't really pushed for significant facilities upgrades (Pruitt is the one behind the indoor practice facility). I think they are very happy with the 9-10 wins a season and the financial benefit that brings. Unlikely that they fire him.
I think Richt has the support from the administration, so I think he is less concerned with public opinion. To me, that makes him less likely to feel the need to get out of Athens (especially for a pay cut, if we believe that Miami is only going to pay $2.5MM). I think he and UGA are both happy with the current arrangement.
There is also the Miami side of the equation. They haven't approached him the two previous times the position has come open. To me that says a lot. There is something about Richt that makes the Miami administration believe that he is either the wrong candidate or he is unlikely to leave. I just don't see them making him a serious candidate this go round either.
I still think that the chances of him leaving (especially voluntarily) are close to 0%. But I also thought Kirby Smart would be a head coach by now too, so who knows.