In my case the vast majority of amazon packages are ups, and most of the remaining are usps.

Also I live in an apartment and no porch/driveway, maybe that's why I dont lose packages :)

Yes they are. Lack of package visibility, unclear accessiblity (vehicle locks), potential of car alarms, requirement for unlawful entry, increased likelihood of occupents associated with vehicle presence, expanded threat for forensic discovery, fear of spontaneous Tesla combustion and vehicle interiors that smell of soiled diapers and spoiled milk are the biggest deterrents.

I'd be amazed if that was true. Even if the packages were visible from the road, surely the barrier of breaking into a possibly alarmed car is greater than just picking up a box from the floor.

I didn't say in driveway. I said in car.