But what was effectively a 'coin toss' decision – undoubtedly influenced by West Midlands Mayor Andy Street – is looking more and more like a major error of judgment.
The Government's integrated rail plan, finally published yesterday after months of delays, pretty much concedes that when it comes to revolutionising Britain's railways, there are far better solutions than HS2.
The plan confirmed the expected scrapping of the extension of HS2 from Nottingham to Leeds, meaning previously commitments to build the scheme "in full" have now fallen by the wayside.
And the PM's own stated reasons for this downgrade paint an interesting picture of where his administration is at when it comes to rail reforms.
The problem with high speed lines, Mr Johnson said, was that they take decades to build and do not deliver the benefits to commuters that are so urgently needed.
Has the PM finally realised that HS2 will predominantly benefit the business world – or at least it may have done pre-pandemic – and that what would really help the country is improvements to long-neglected local networks?
Remarkably, in his reasoning for cancelling part of the line, Mr Johnson also noted that HS2 would "smash though unspoilt countryside and villages".
There's a phrase about excrement and Sherlock that immediately springs to mind.
What Mr Johnson needs to do is admit that the country simply doesn't need HS2, and put the whole project on hold and under review.
Because as things are, it is swallowing up the vast majority of funding for this country's transport infrastructure.
This is billions of pounds that should be being invested right now on schemes in the West Midlands, such as the reopening of local lines that were closed down decades ago in the Beeching cuts.
And while local leaders seem very excited that the Government has backed the Midlands Rail Hub, not a single penny of the £2 billion required to fund the scheme has been committed.
That particular project is still at an embryonic stage and no business case has yet been developed. Ministers are adamant it will go ahead.
However, similar promises have been broken over Northern Powerhouse Rail, and Mr Street and the transport planners at Midlands Connect will no doubt be privately concerned that the same thing could happen again.