“but the Austro-Hungarian Empire would have survived”
Probably not...
Ethnic nationalism was plaguing the Empire badly in the years leading up to WW1, and it was already “Balkanizing” when the War began, sped up by incompetent management from the top. The Empire had been in decline ever since it’s defeat by the Prussians in 1866.
As one researcher puts it, “they were living on borrowed, time, if not borrowed decades already. It was a prison of various nationalities looking for escape.”
Archduke Franz Ferdinand had a solution. He wanted to give Slavs, or at least Croatians, equal footing with Germans and Hungarians. That is why he was killed.