IL-2s were actually tough a/c to shoot down, its easy to endlessly quote (which we all do cuz its interesting) the exploits of the top 1 percent, and then act as if thats the "norm". The things they did were extraordinary because they were the top elite in their respective air forces.
As for Hartmann, just because he had a certain # of kills would have been no guarantee he would have survived the war, war is cruel, there are many 100+ LW vets who who were KIA in 1943-45. Even the best of the bests luck runs out at some point. Its nothing but idle speculation past that. Death by "other means" ie; mechanical failure, collision, weather, ect, was also a constant danger, and in his case, thats what happened. It was a cause of so many missions his number finally came up.
Look at Von Richtofen in WW1, all those missions and close calls, in the end, he just had a bad day, and thats all it took.