... except these stories of non-lifters lifting cars and such are well-reported. Remember that the physics of lifting a car is very different than doing a deadlift or something. In these stories, people are just lifting the car a few inches or so to save someone pinned underneath. Hydraulics provide a lot of momentum, and the person pumped full of adrenaline lifts the rest. Once she gets it up high enough, she has to hold it long enough for the person to get out. Static strength is much stronger than concentric strength. In a lot of these cases, people tear their muscles and tendons. For the most part, strength IS in the mind. The nervous system has a lot more to do with it than muscle size. Human genetics inhibit what their nervous system puts out in normal circumstances, but that limit can also be turned off.
Think of a chimpanzee. It's four feet tall and weighs 100 lbs, yet it can lift a thousand pounds without even knowing what it's. A chimp's muscular system and nervous system are basically the same as a human's with one exception, namely how well it can control nerve firings to contract its muscles. Humans evolved to inhibit the intensity of these firings so as to gain precise control over their muscles and develop fine motor skills. We don't need raw strength because we have raw intelligence that allows us to build machines stronger than any animal.