With old technology ropes, you are correct to be untrusting, but there are ropes made with modern fibers that have unreal strength, wear resistance and low weight.
As an example,
AMSTEEL-BLUE - Samson Rope. Dyneema is the name of the fiber. There are others brands and various grades with in brands as well. Some could be strong, some weaker, depends on what one needs.
Example:
1/4 inch galvanized wire rope has a breaking strength around 7,000 pounds and will weigh in around 11 pounds per 100 feet.
Amsteel Blue 1/4 inch rope has an average breaking strength of 8,600 pounds, with a minimum of 7,700 pounds, and have a weight of 1.6 pounds per 100 feet.
Later,
Dan