Having lived in the UK and the US, I think a strong reason is that the copper wire is literally entrenched. There seems to be a strong (legislative? legal? political?) aversion to easily replaceable overhead wires. Underground cable is the strong preference here. At the moment I live in the city centre of Manchester (the second or third biggest city depending on who you ask) and am stuck with VDSL.

There are other problems as well - arguably there is no functional market for internet here. The UK is quite a small and centralised but for whatever reason cannot deliver infrastructure to "rural" areas that are only 50 or so miles from the largest cities in the UK, e.g. Wales.

I have co-workers who have moved into new builds with only copper to the building.