Hi guys, I came across this sentence in the TIME Magazine, but failed to really comprehend it like I do before.
" This early and aggressive emptying of the region - a hard-earned lesson of the 2003 fires, which left 20 people dead - likely saved Californians' lives, if not their property."
The bolded part is the part that I didn't really manage to grasp the true meaning. From what I comprehend in the past, when ", if not" is used like in the sentence in above, it actually kinda means that you are choosing one situation between two. For example, "This collision would have paralysed him, if not cost him his life." would mean that the collision would either paralyse the guy or worst still, it would have killed him. Therefore, if I would to apply my understanding of the use of ", if not", this sentence from TIMES would have not make sense to me as it would mean that the clearance would have either save the lives of the people or their houses.
Some please enlighten me

Thanks in advance!