it,s the country that needs fibre not the city.

SM Repeaters have transit times.
They have to fully receive a packet before they repeat it.
So each time the packet passes through a repeater the same delay would
occur. Believe me, been there done that.
High gain antennae at the customer site is what I said, yagi antenna
with 12 db gain would help no end.

A high powered site could serve a considerable area and would save the
cost of all those repeaters and be faster as well.
There are a number of VHF and UHF analogue TV channels becoming
available and a few of them could be used for the NBN.
Much more reliable, greater coverage and not subject to rain fading.