In the words of a certain, in my opinion pretty much spot on railway engineer and podcaster, "abolish the treasury, folks".
No wonder everything seems to be falling apart in this country when investment is seen as a bad thing, apparently by people right across the political spectrum. The "no wonder politicians don't want to spend money on the railway, look how little gets done with that money" argument is flawed on two ways:
1. Even if it costs at lot, it can still be worth it. We need a really big increase in public transport capacity over the next couple of decades to meet decarbonisation commitments, and benefits extend far beyond fare revenue into the enablement of a better, healthier and more welp connected society.
2. The reason this stuff is so expensive is partly because the government refuses to organise the industry in a sane way, and at the same time keeps chopping and changing projects all over the place rather than making long term plans and sticking to them.
I think £96 billion is the amount reserved for HS2 and NPR (which includes TRU) in the current plans.
That's a huge investment in rail, much of it in the north.
Yes, the plans are too vague to work out the impact on current services, and will take maybe 15-20 years to deliver, but they are there.
DfT are not going to spend large sums on altering the existing network when the new lines will change the entire network around Manchester.
The other issue is that the railway seemingly finds it impossible to deliver major projects to time and budget (eg WCRM, Crossrail, electrification, HS2).
Not always the railway's fault, but they get most of the blame nevertheless.
The Treasury (any government) simply does not trust the railway to deliver, hence the hand-to-mouth piecemeal plans, and the micromanagement.