Old cars were not sturdier or more robust than new cars. That’s a myth. You can Google “crash test old car vs new” or something like that to see examples.
90s volvos were absolute tanks . My friend had one and it got rear ended while parked and both the car that rear ended it and the car in front of the Volvo got totaled. The Volvo was pretty much fine and just needed a new bumper (which was easily done as the bumpers were distinct from the body work).
I believe it's at least partially true, because new cars are designed to be damaged in crashes, to better protect the people inside them.