They got 100Mbps wireless in Iceland (country)
In Iceland (since I don't have other information) they got 100Mbps to users on both 5Ghz and 3,5Ghz using both 802.11ac and LTE (3,5Ghz). In Denmark, Norway, Sweden and I think Finland they are using LTE on 450Mhz for speeds that are close to reaching 100Mbps (along with other frequency bands if available and that's not always the case). What is limiting factor on 450Mhz is lack of Mhz (frequency bandwidth).
For that reason I don't understand why this is a problem in Australia.