The furcate pre-insulated terminal is easy to connect with electrical wire to strengthen its reliability and safety.Used widely in the machiney, electric power, railway, shipbuilding, aviation, home appliance, computer or other automatic equipments.
There's another shape available if you want to make your first drawing.
On the car, the "ground" is just the metal of the car itself. Provided the ground plane is larger than (I think) 1/4 the wavelength all is good - without a real earth ground.
Had a situation many years ago where we had a portable mobile two-way radio in UHF with an antenna with a magnetic base intended for use on cars/trucks. We needed to use it without the car or truck (two stories up, out of the window on a masonry building.) No earth ground, and no ground plane. The dealer gave us a square piece of sheet steel somewhat longer than the antenna. Antenna on the sheet, balanced on the window ledge, prblem solved.