Insurance will total it.
My brother was re-ended in his 1988 Grand Marquis. To keep the value of the damage below the total threshold, he did some of the repairs himself before letting insurance see it. Kept the damage under the totaling amount so insurance did repair some of it and they did not total it.
Six months later or so, another guy ran into the back of his 1988 Grand Marquis. This time the damage was more extensive. He went ahead and went to the insurance company with the car as is. They totaled it. However, he did still fix it up and went to Brake and tailight inspection, CHP inspection, etc. to get the salvage title back to a normal title. So I guess if you love the car, there are still options to get it back on the road.
2003 Mercury Marauder 300B (Daily Driver)
1988 LTD Crown Victoria S