Correct, but that is necessary in order to get a relatively lightweight and flexible cable to carry huge loads. It’s not nearly as important for an adapter which is, for the DC pins at least, a solid bus bar encased in heat resistant plastics.
I was thinking that the contact resistance would create quite a bit of heat as well, and if there's nowhere to dissipate you can get quite hot. Even if a high temp plastic can take it, you might burn the person handling it.