truckyboy:
I remember the days when we had to supply our own entertainment…a radio with a powerpack was the norm in cars…but in my maudsley i had to fit an 8 track, then when i got promoted to a thames trader, took it with me, well that was till the cassettes player came about…whats all this with a cd, i thought thats what you needed to get a job…how times have changed
Anyway, until recently, my car had a Cd player and cassette ( all in one ) with multi changer ( held 12 ) but since i changed cars i only have a cd, but it does play mp3 so thats all good but sadly no multi changer.I think your boss is being mean fisted by going for the cheapest option of a bare basic radio, with no cd player. as for paying £10 a month for spotify, no thanks i
ll continue downloading and putting it onto cds that i can take in the truck and the car, and even from youtube as well..illegal or not, but i literally have hundreds of cds full of the music i love.
Ironically I’ve still got cassettes and the original cassette player in the Jag and the old home JVC cassette deck I’ve had since the 1980’s with loads of music on cassettes going back to the 1970’s.While I never got round to getting a CD recorder.But only have a CD player in the Zafira but which won’t play DVD’s although I’ve got a DVD recorder. 
In which case the most practical option seems to be to replace both cars’ radio cassette or CD with car radio/DVD player options. 
Which leaves the problem that the agenda seems to be the eventual removal of the CD and probably logically DVD options.Because the corporate world stitch up knows that Tivo/hard drive type home recording media is totally incompatible with mobile car etc use.Which they obviously intend to force along the lines of the subscriber only mobile phone/Spotify type of set ups.Which answers the OP’s question in that it’s probably more a case of that agenda than the thing being specced with just a radio.
On that note I’d guess that I phone and USB would be the next best option.Although again obviously dependent on paying for an expensive phone and phone data charges and fitment of USB capable radio in the truck. 