I think your timeline re: maggie maybe a decade out. But it does ssem Openreach/BT have made 2 important discoveries.
1) that FTTP is ultimately the better technology, both future proof and significantly cheaper and more reliable in the long term that FTTC.
2) that ECI FTTC was a poor choice

I think your timeline re: maggie maybe a decade out.

It is certainly wrong to some extent as Maggie was removed from office before the end of 1990.

I remember seeing the fibre being shown on Tomorrow's World in the 80's and that after showing how amazing it was BT changed their plans because the government would not allow them to broadcast TV over it (which was the main business case for them).

From Wikipedia "Margaret Hilda Thatcher, Baroness Thatcher, LG, OM, PC, FRS, FRIC (n�e Roberts; 13 October 1925 � 8 April 2013) was a British stateswoman who was Prime Minister of the United Kingdom from 1979 to 1990"

I remember her leaving the office of PM very well - it was shortly before I was made redundant from my first full time job so I remember the year - don't normally know when things happened in politics quite so well.