They don’t need to be really but we’ve got what we asked for... massive heavy wheels so need lots of compression damping to control the undamped mass. Big engines, massive cog filled gearboxes so heavy easy to package struts rather than expensive multi linked suspension. Total lost of tyre compliance with mega low wide profiles and runflats. Motoring journalists slate cars for not having as stiff chassis, or being slower than the last model on the ring. Big power, loads of grip, massive brakes mean big forces so all the bushing is really stiff. Fat anti roll bars which help with roll but also take away the comfort and traction merits of independent suspension. Stiff “sports seats” Low ride heights meaning to compensate stiff suspension. Direct mounted racks for precise steering feel...... the list goes on...