First of all, the 46/LTE require some bandwidth for upload and download. The lowest bandwidth for LTE is made to match the frequency spacing for DAB (It's actua

First of all, the 46/LTE require some bandwidth for upload and download. The lowest bandwidth for LTE is made to match the frequency spacing for DAB (It's actually prepared to replace DAB) with 1,4 MHz channels. FM slots for broadcast is regulated as slots with 100 kHz. A slot with only 100 kHz bandwidth will give you modem speeds, like 24,4 bits/s. So there's just not revenue to make so small speed for modern broadband networks since everyone need to share the channel. The other issue is that the band 88-108 MHz have so big coverage, so there will be problems with the cell spacing. So 4G via FM is not a business case. However, the DAB channels are already planned for 1,4 MHz LTE. So guess what will happend in the near future?