I can imagine where this investigation might be right now if George had done what he knows should have been done at that impound yard. If he had followed his police training, after smelling the odor in that car he would have stopped right then and called 911.
George didn't know what had happened in that car. There could have been all sorts of scenarios. Even if he knew Casey was alive and well because Cindy had spoken with her during the time that car sat at the impound yard, he hadn't laid eyes on Caylee or spoken with her in more than a month. Even if Caylee was okay, there are other possible scenarios involving that car. It could have been stolen and used in another crime. George knows what he should have done.
If George had stopped and called 911, the OCSO would have impounded the car immediately and questioned George and Cindy. When LE learned that the abandoned car was used by the Anthony's daughter and that she had left the family home a month prior, and that the grandparents had not seen or heard from their granddaughter in that time, LE would have searched for Casey and Caylee. LE would have questioned Casey's friends and would probably have found Casey at Tony's apartment, just like Cindy did, and questioned her. When Casey couldn't produce her daughter, Caylee, they would have questioned her. It's likely that the end result would still be the same with Casey arrested for obstruction of justice and child neglect. But her story might be different.
The difference is that Casey wouldn't have had time to confer with her brother and parents, and had time to come up with the babysitter story. LE would have had the car, untouched by George and Cindy, with all evidence intact. There likely would have been much more in the way of forensic evidence for LE to work with in that car.
In any case, I think LE would have more evidence and we would be discussing a different set of circumstances.