Yeah I get there is a huge difference, which ironically is likely to make CityFibre cheaper and easier to deal with. They shouldn't suffer the same issues where when a problem occurs OR can blame BTW and BTW can blame the ISP. Starting from scratch I'd imagine the whole network can be more efficient due to not having to deal with legacy cruft, although probably has less redundancy in the ISPs PoP?
I still wish we had less reliance on all ISPs terminating in London, so that gaming between people within the country could route more directly - but then the latency now were going to fibre and games all moving to being server-based anyway, makes it kinda redundant anyway. Its just eye opening when you've been on a local network (Digital Region) where peer to peer traffic to another person on the same network was almost LAN latency.