The Volvo 140 series unibody, released in 1966, was good enough to survive into the 1993 Volvo 240 with only minor alterations, with many experts still regarding the 240 as one of the safest cars in the world when it ended production, so that’s probably an early example of a good unibody. But before that? Maybe Mercedes that was a pioneer when it came to crumple zones, but I would think that many early unibodies is either beefed up everywhere and too stiff to crumple, or too weak and will fold like tinfoil in crashes. So you’re probably right…