When FM radio dies, modern, digital DAB radio will become the norm. The problem is, the day FM radio dies is a loooong way off, because there would need to be so few people using FM in order for them to switch it off.
Digital downloads is DAB radio.
I don't see CD production ceasing. Like vinyl, it will continue, but may well be on a smaller scale due to the size of the used market it is competing against.
I myself buy more CDs now than I ever did during the 90s, many are used if I can pick them up for a quid or two, but when used CD prices are high, or approaching the new price for a specific release, I'll buy new.