Where are you reading that twisted pair copper lines can support 5 or 10 gig speeds? Most I'm aware of is 2 gig on a very short run using G.fast. And that introduces additional complications into the network versus a simple passive optical network that's all fiber from end to end.
In the post you quoted I was talking about the twisted pair (cat5) from your service entrance through your walls to your router, using ethernet.
For telco twisted pair (cat3-ish) there's G.fast, but there is already a faster version of G.fast that hits 10 gigabits at 100 meters, and research into using the wires as waveguides that can hit a terabit at that distance (and 10 gig at a half kilometer, which would make it a drop in upgrade to VDSL2 deployments which are generally within a half kilometer of the fiber cabinet)