I'm fully aware OR are to blame for the issue round here
Why not the builders who failed to make the necessary arrangements?
There are lots of former brownfield/commercial sites especially in London where connections are on long EO lines. These were more than adequate when landlines were all they were needed for but clearly not suited to modern digital communications. Upgrading circuits and network rearrangement is expensive and BT as a commercial company answerable to its shareholders invests its capital where it can expect a commercial return.
The problem with the former docklands and other brownfield sites is that in the major urban areas such as London, Leeds and Manchester no BDUK funding was available to gap fund upgrades between what was commercially viable and the total cost. So rather than BT you might instead want to criticise the politicians - of all colours - who set up and ran BDUK.