When you buy a new-ish car, it will generally have a factory warranty. This means for a period of time and/or mileage- say, 5 years/100,000 miles- the dealer will handle otherwise expensive repairs.
When the warranty expires, the owner is completely financially responsible for repairs going forward. That can be a frightening prospect for many people, especially the elderly or poor.
Predatory warranty companies prey on this emotion by aggressively marketing non-factory “extended” warranties that claim to provide the same assurance that the factory warranty did.
Generally however, these warranties are little more than scams- with extremely high deductibles, limited parts coverage, or numerous escape clauses that allow the provider to deny coverage. Or, it’s a scam entirely meant to harvest financial information.
The reason that the extended warranty scam is so culturally notable is that car registrations (in the US, at least) are semi-public record, so these companies can see when someone buys and registers a car- and aggressively solicit them. So a large portion of the population has experienced it.