Do cars still come with steel belted radials or are tires made of something else these days?
Tyres still have steel belts, as well as Kevlar and similar composites. It's a balance between cost and weight.
Cheap have steel. Expensive ones use kevlar.
Depending upon the tyre application it can have steel belting, polyester belting, or kevlar. Many have a combination of two polyester plies and one of steel.