Fiber is sexy and all that but DOCSIS3.1 is easily capable of 10Gpbs. There is no need to spend all that money on fiber, not yet.
quote:
DOCSIS 3.1 - Released October 2013, plans support capacities of at least 10 Gbit/s downstream and 1 Gbit/s upstream using 4096 QAM. The new specs will do away with 6 MHz and 8 MHz wide channel spacing and instead use smaller (20 kHz to 50 kHz wide) orthogonal frequency division multiplexing (OFDM) subcarriers; these can be bonded inside a block spectrum that could end up being about 200 MHz wide.[7]
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en.wikipedia.org/wiki/DOCSIS