AM and FM broadcast radio are licensed in seperate spectrum in most of the world (AM on the medium wave band, FM in VHF). Broadcast FM didn't replace AM radio o

AM and FM broadcast radio are licensed in seperate spectrum in most of the world (AM on the medium wave band, FM in VHF). Broadcast FM didn't replace AM radio outright, and there are still loads of AM stations. In some very rural areas in North America, it's the only broadcast radio you can receive. There was also a significantly longer gap between the instruction of broadcast AM and FM and the gap between DAB and DAB+.