Interesting!
There's actually a planning model which shows better cost-benefit outcomes by investing in those parts of a network which ARE MORE REMOTE from the hub/capital and which have LOWER passenger useage.
The 1st reason for this is simple - its so much cheaper to build (for example) 50 miles of new rail thru Lincolnshire, Somerset, Hampshire, Northumberland, Shropshire or Stirlingshire ; than 50 miles thru London or other any densely populated areas.
The 2nd reason is more complex - if we introduce the comparitively modest numbers of passengers over the more remote stretches, but realise that they are partly NEW passengers because of the increased speed, and then we add them to the long distance passengers who only become NEW passenger BECAUSE the further reaches of the journey have become accessible, then we get a massive increase in passengers per investment.
Simply put: if we create several 50-mile-long 300km/hr sections far away from London and just upgraded some of the existing links out of London, then we'd get lots and lots of new journey routes becoming attractive to passengers because of their speed, their availability and connectivity, at a much lower investment than new platforms in London and new routes thru London.
As 3 quick examples, think of the impact of just:
300 km/hr links between Bristol & Plymouth, Edinburgh & Perth, Leicester & Liverpool, Sheffield & Leeds. (these are just to illustrate the theory, not researched examples).
All cheaper than building anything in London, Birmingam & Glasgow.