How about "Survived the tests of time."
Did the body, paint, interior, wiring, suspension, and drivetrain survive?
This is to say; Does each aspect function as originally intended?
Functions;
Body - Hold true to it's design/ shape and assembly
Paint - Look appealing, seal the body from the elements, including add-ons.
Interior - Instruments serve as intended, upholstery is presentable and clean as it's design intended to be
Wiring - Carry correct voltage and function, with correct fitment and finish
Suspension - Ride, handle, hold true and seal
Drivetrain - Run in good tune, operate correctly, seal and carry the correct finish
Maintenance components were intended to be replaced as needed, so doing things, like changing them out for the correct ones, shouldn't be considered to affect it's status as as a survivor, however, each component changed is only original once, including the oil in the crank case, grease dobs on battery terminals and air in the tires, if we're talking about forensics, here. Those things have very little impact on a survivor status, IMO.
Each aspect of the car has a toll on its percentage of survival rate. It's really that simple and not a very difficult analysis.