UPS trucks are custom designed for UPS; they used to have a nice documentary about it. New Amazon trucks around where I live are clearly custom (and also not very pretty, if you ask me).
All I could think of was “they repainted an Amazon van“.
I know Rivian makes them all. But seeing so many Amazon vans has changed who “owns“ the design in my mind.
Since it costs extra, Amazon will only adopt if if they're forced, either by regulation or significant social pressure.