Hard to compare what "crazy" expensive is but I bought a pair of these for $90 https://amazon.com/dp/B01MRV4WA1. For the 3 places in my house I wanted to wire with Ethernet, I was done under $300. Patching drywall, paint touch-ups, new cables, and the overall time and headache would have cost a lot more. I was done in a matter of minutes using old coax and these adapters.
In my case, I didn't build a MoCA network, just used these devices point-to-point. If you go full MoCA, think of it like a distributed hub - no switching, no routing, no security. In fact you should put filters to prevent neighbors from listening in using their own MoCA adapters. For me, point-to-point worked. YMMV but Ethernet over Coax is definitely worth looking into for upto 1gbps speed, which is plenty for wifi, netflix etc.
> Who knew that inbound cable internet has outbound data capability?
The physical medium isn't directional, so there's no reason to assume it would not transmit and receive. A coax cable is equivalent to three wires with better isolation from the environment (and with one "wire" usually used for ground).
There's an asymmetry in commercial broadband over coax, but Im not sire why that is precisely. Perhaps someone familiar with DOCSIS etc. could say.
In my case, I didn't build a MoCA network, just used these devices point-to-point. If you go full MoCA, think of it like a distributed hub - no switching, no routing, no security. In fact you should put filters to prevent neighbors from listening in using their own MoCA adapters. For me, point-to-point worked. YMMV but Ethernet over Coax is definitely worth looking into for upto 1gbps speed, which is plenty for wifi, netflix etc.