I completely agree! In my other cars, I changed or installed beside a DIN 12V socket and all devices I am using in the car have got the responding plug. This is save solution. For use in other cars (e.g. rented cars) I have an adaptor DIN<->cigarett-lightener socket, Just a short cable.
I got curious and found this source on the internet
RoadPro 12V and 24V Plugs, sockets and adaptors The only thing is that I can not find a DIN 4165 to USB converter. Given that most mobile phones and some other devices now use a USB socket for charging (5v) I am surprised that it does not seem to be available.