Right now, a lot of commercial broadcasters are abandoning broadcast frequencies below 1.8 Mhz. They're turning off the transmitters and handing in their broadcasting licences to the issuing authorities. In the USA though, some AM broadcasters are successfully acquiring "FM Translator" (relay) stations. Technically the relay/translator station is supposed to re-broadcast the signal of the parent station, but in practice the relay/translator receives a direct feed. It's a way that a broadcaster can get a FM signal where there are no full-power licences available. Other reasons why broadcasters may keep the AM turned on if they got no listeners on the AM frequency is streaming; broadcasters pay less in music royalties than do Internet-only streamers. It's one reason why Pandora purchased a broadcast station.
iBiquity's IBOC and Digital Radio Mondiale's technology could resuscitate the "AM band", particularly in ITU Region 1 (Europe and North Africa) where "long wave radio" still serves large populations with a single high powered transmitter. Music was a main reason why people left AM for FM, so fm-like sound quality on HF, MF and LF bands can make these bands attractive to broadcasters again.