I'm sure some (plenty) of Brits do still plug-in their TVs to those antennas, but anecdotally I can't think of a single friend or family member in the UK who I've noticed still doing that.... most either use a TV package from their ISP, or no TV at all. And yet we all still have those antennas on the roofs because why bother removing them?

On the other hand, doesn't Virgin Media (pretty much the only cable provider in the UK) use coax into routers/TV boxes?

sorry to be snarky there. Your post read to me like, "I haven't seen a banana in the US in 10 years. We don't eat them anymore."