The cars are too big for that circuit. They just looked like lumbering, yet fast, beasts.
They're using the platform size of a full size US SUV (Ford Expedition / Chevy Suburban), with all the bits designed to fit into a center of gravity below the wheel tops.
It got me wondering if the regulations that created these monsters developed as an aero response or because of considerations with hybrid packaging needs. I know Max Mosely was concerned about slowing the cars for safety, so the size may be to do with protection zones. On the other hand it would not surprise me of he and Bernie just wanted larger cars for more sponsorship logo potential.
The main cause of the length of the cars is the aerodynamic advantages associated with it.
As there is no overall restriction on length, though the front and rear overhangs are a function of deformable crash structures. The presence of many crash structures and other safety features contributes to the weight as well. Packaging the turbo and hybrid components also contributes to size, and most teams would rather place these components in a line to increase length and decrease cross sectional area.
Overall, a narrower, longer car will produce less drag, and the air can be worked to create downforce more easily. Think about it as the different between the first chicane and the Ascari chicane at Monza. For the same speed, the latter is much easier to drive through because the curves are wider,
Of course the width is mandated and is currently equal to cars from 1993 to 1997.
The size of these cars has little to do with Max Mosley and Bernie Ecclestone, especially the former. Mosley generally wanted to lighten the cars as a lighter car carries less energy into a crash. However, that means they experience higher accelerations, so from the driver’s point of view, a heavier car can be safer.
I totally get that smaller, lighter cars are more fun to watch, as they’re less stable and more affected by external forces. So they move around a lot more and are visually interesting. But you’d have to mandate smaller cars, because for a long time greater performance can be produced in larger cars.