Since you mentioned cars, here is a theory my coworker told me that I think makes a lot of sense.
Our parents were the last generation to learn about cars because back then you needed to know how a car worked in order to own one. Cars are too simple now and you couldn’t fix one even if you wanted to since they are so locked-down.
We are the last generation to learn how computers work since we needed to know how a computer worked in order to use it. Now computers are too simple to use and you couldn’t fix one even if you wanted to since they are so locked-down.
Obviously not saying nobody today knows how cars or computers work, but it is a lot less common. Anybody who learns about cars or computers today do it because of personal interest, not because of necessity.
Sorry I meant simple to use. Repair and maintenance is very complex. You often can not even do some maintenance since you need specialized tools or software that only mechanics have access to.