This is spot on. I do quite a bit of DOCSIS engineering work and this is a very good explanation.

It is going to vary quite a bit depending on your MSO and location but the "neighborhood" in modern DOCSIS deployments is getting smaller and smaller with Remote-PHY and N+1/N+0 deployments. What was traditionally 200+ customers on a node is shrinking down to much smaller numbers (dozens vs hundreds).

One guideline that is often thrown around is that the node will have at least twice the bandwidth of the highest speed tier and capacity is often added in excess of that based on usage and node size. You can also get fancy with dedicating channels to specic packages, so some of that bandwidth might only be "shared" with other customers on the same tier service as you.