Cars of yesteryears were predominantly made with metal.
Progress and evolution have made this practice not the general rule anymore.
More and more plastics of different compositions have gradually replaced metal.
Good examples are bumpers, car exteriors and interiors...and by that, it's a lot!
The engine bay hosts a lot of these plastics as well.
There also exist, parallels in small scale car miniatures.
I guess plastic will continue to exist side by side with metal, as both have their distinct advantages when used in cars. Whatever the scale is!
I have recently been receptive of the appeal of plastics as well.
This pair of VW 411, illustrates the individual charm of each material.
and diecast base chassis.