Thing is the whole electorate have been told that's precisely the case for like 15 years; how do you change/challenge that? And as soon as you do, the election messaging for the opposition is a piece of piss, and will likely be successful.
I won't pretend to know/understand/believe that it's sustainable to run on a permanent deficit (presuming that's the alternative, seems like there's only two options really) and haven't got the energy for that conversation, but optically/politically even, how would you do it and survive in power?
2017, the narrative from Labour was significantly different to the status quo.
Labour launches its manifesto ahead of the general election. Here are some of the key points.
www.bbc.co.uk
There is absolutely no way that much of this manifesto could have been delivered and keep the fiscal rules that have been the straight jacket of governments since 2010.
Labour 2017 12,877,918
Labour 2024 9,708,716
To be clear, I am not suggesting that over 3 million more people voted Labour in 2017 because they were ardently in favour of expanding the state and hiking taxes - there are Brexit related contexts in 2017 (as well as a piss poor Tory campaign) that had an impact on that election. It does show, however, that at the right time an alternative narrative can break through and not be roundly rejected.
It is arguable that Labour could have gone into the 2024 election with the 2017 manifesto and still won - the Tories were a shambles and the smaller parties have First Past the Post to contend with. But, it would have meant ditching the commitment to the "fiscal rules".
Would it have gone tits up in power? Possibly. But the Winter Fuel Allowance wouldn't have been cut. The Budget would have focused tax rises on wealth.
We have only had a budget surplus in 7 years since 1975, 4 of those were under Blair and Brown - we are effectively in a permanent deficit and the fiscal rules do little to impact that. Firstly, they are a simple solution to a complex problem and secondly, they are set by Government who can change them at a whim if they don't like the consequences of their rules...the Conservatives changed them frequently.
If fiscal rules are to be of any use, they need to be set by people who know what they are talking about and not Governments. If there was a genuinely independent "fiscal rules body" that set out what a sensible set of rules are to achieve sensible outcomes Governments and those aspiring to govern would have to shape their policy offer to fit something that people had some confidence in.