You don't even have to go to a different class. A Model 3 weighs about as much as a BMW 3 series and both weigh slightly less than the average new car.
A lot of this is modern safety features. Crumple zones and stronger roofs add weight, more weight implies bigger engines, bigger engines require stronger frames, soon the average car is two tons. Volvo S60, Mercedes C class and Audi S4 are also a similar size and weight. The makes from the US and Japan are a little lighter but not dramatically lighter and their safety ratings are also a little worse.
It’s also a testament to the improved efficiency of engines. Once your engine can deliver a few extra MPG, it’s easier for companies to pack more weight on.
