[wat10000]

It's a lot easier to upgrade the capacity at a central office than it is to upgrade an entire neighborhood. Plenty of cable infrastructure was built out when it was just a broadcast (multicast?) medium and the only concern was making sure signal strength was adequate at all receivers. If you repurpose that wiring for emulated point-to-point transmission, there may not be a whole lot for each individual.

Random example, my house has fiber and cable available. The internet plans are similar, except fiber offers 30x higher upload speeds, which is a direct consequence of better topology.