simguru, in urban areas ,regular LTE is already working as an affordable fixed access technology, in countries like Austria and South Korea. Maybe not Gbit to the home, but probably 100 mbit+ .
And yes there are issue with mmWave, but still, the fact that verizon is ackuiring tons of 28GHZ specturm for that role ,together with others , indicates that it does make financial sense, probably.
And some startups like cohere and tarana do offer solutions to problems the lower parts of the spectrum, like solving fading(cohere) and solving non-line-of-sight + intereference (tarana), and there are improvements in using large number of antennas(MU-MIMO) to achieve maybe 10x better spectral efficiency.