It wasn't a health concern. The only concerns for 5G were long-term practicality, energy and service costs and shorter coverage.
5G was supposed to be made for robots, IoT and wireless home internet.
I haven't tried 5G, but it seems that the expected speeds would be the same as 4G in early days.
I think 12/1 Mbps runs around $60 a month in Australia. It's possible to get it a bit cheaper but those are usually plans that have a data allocation.
Yeah. Apparently it was killed by lobbying to ensure dependence on cable TV and traditional news media. It's not entirely different to what happened in the US that one time.