The bard himself would have penned a thought on what has occurred.....2b or not 2b, that is the question...
Interestingly, if you look at the regional rail use for 2022/23 (so about a year ago now), from 2009 to 2023 the HS2 model anticipated growth to 136 passengers for every 100 in 2009 whilst the current achieved is:
Northeast 147
Northwest 128
Yorkshire and the Humber 128
West Midlands 123
East Midlands 100 (i.e. no increase since 2009)
Scotland 220
Based on those increases it's reasonable that the East Midlands was cut, however it does imply that getting to Scotland is a priority.
Although, that increases don't show the whole picture. Not least London/Scotland was starting from a low base. In terms of actual passenger numbers the current flows are:
Northeast 2.8 million
Northwest 8.4 million
Yorkshire and the Humber 7.2 million
West Midlands 9.8 million
East Midlands 7.9 million
Scotland 3.2 million
That does imply that going beyond the West Midlands to the west does make sense with at least as many again heading beyond Birmingham as to Birmingham (not least because Birmingham ≠ West Midlands).
Even if HS2 doesn't extend to the East, it would (by providing capacity for Scottish travel) ease congestion on the ECML to serve Yorkshire & the Humber as well as the Northeast more than it currently does.
Whist when compared to pre COVID the numbers are a mix again (pre COVID peak=100, with numbers below meaning a gap and numbers above meaning a rise):
Northeast 107
Northwest 74
Yorkshire and the Humber 94
West Midlands 68
East Midlands 81
Scotland 125