I'd agree with all of that and just add that the principal reason behind it was to provide extra capacity to serve short-distance movements into London by switching the longer-distance traffic to the new line — logical enough, as it's very much more straightforward to build a new line than widen an existing one. If you then build the new line to high-speed standards you can brag about bringing Birmingham closer to London and about the time-saving to be gained in the distant future for places north of Birmingham so as to take attention off the fact that it's really all for the benefit of London. So much money, that could have done so much to modernise and improve the existing system to a much shorter time-scale, bringing real benefits to places like Liverpool, Leeds, and Manchester which, apart from their links to London, do not really have fast modern train-services to any other destinations.