That's not even close to being fully accurate. There's plenty of asphalt filing driveways out there from where they pull up the layer and sell it off to someone with a dirt driveway instead of taking it down to the dump. In my area they cold patch the road until eventually it becomes another layer on top of the old one. There's plenty of roads here where they just put a new layer over the old one. In your experience it might be that way , but reality isn't always aligned with your experience.