I find the same to be true about parcel delivery in the United States. Although I'm sure delivered goods -do- get stolen off of doorsteps all the time.. it appears to be relatively safe enough that people do have things delivered to their doorstep and just dropped off there left in clear view until they get home.. and most of the time apparently not have them stolen.
That totally depends on the area. I live in a moderate sized US city, not really even a bad area, and I've had tons of packages stolen off the front porch. I finally had to just rent a mailbox to ship packages to.
In the suburbs, you can get away with it because the houses tend to be back from the road and there's not a whole lot of foot traffic. It's often not easy to even see a package from a passing car, and you'd be conspicuous as hell stopping and running across the front yard to grab it. In a denser neighborhood like mine, the houses are five steps from the street and there is lots of foot traffic. It's a piece of cake to step up, grab a package, and disappear before anyone notices.