It’s a running joke in Westminster that some on the British centre-left are fascinated by American politics to the point of obsession. So much so that it extends to the fictional: in 2006, a group of rebel Labour MPs inspired by the long-running US drama the West Wing borrowed tactics from its plotline to successfully defeat the government in a vote. It’s right, therefore, to be wary of over-extrapolating lessons for the Labour party from the Democrats’ presidential defeat.

But with inflation again on the rise, there will be more parallels between the economic backdrops to the Kamala Harris 2024 campaign and a 2029 Labour general election campaign than the party would like. There have been reams of analysis on why the Democrats lost, but the most important takeaway is that, in the context of living standards eroded by high inflation, a candidate who found it difficult to connect with voters and struggled to explain why her party should be given another four years was punished accordingly.

It’s not just the Democrats: in New Zealand, Japan and South Africa, governments have been booted out of office in what the academic Rob Ford has called “the greatest wave of anti-incumbent voting ever seen”. Worryingly for Labour, there is little to suggest that this curse of incumbency is going to lift anytime soon.

Labour’s first few months have been dominated by a series of political rows very much of the present: the out-of-the-blue announcement about means-testing pensioners’ winter fuel payment; questions about ministers accepting freebies, including from companies where there are potential conflicts of interest; the fight with farmers over inheritance tax. But an even bigger headache lies ahead: the gap between voter expectations and what Labour might realistically be able to deliver in the next four years.

Voters have lost faith in politics to deliver and are desperate for things to get better. Polling from More in Common shows just 31% of people think democracy is working and 62% think politicians aren’t up to facing the country’s challenges. Trust in politicians has more than halved since the mid-1980s. The most common word people use to describe Britain is “broken”.

More in Common director Luke Tryl tells me there is an overwhelming feeling in focus groups that, despite doing the right thing and working hard, at the end of the month people feel as if they have nothing to show for it. He thinks that the steep fall in Labour’s approval ratings isn’t just a product of the government’s shaky start, but a huge impatience for things to improve.

The problem is that Britain’s challenges are probably too big to fix in five years. There are the long-term structural issues with the economy – low investment, sluggish productivity and sharp regional inequalities – made worse by Brexit; and the state of the NHS and so many other public services, from policing to older care. And that’s before you factor in the longer-term problems: a housing crisis that means many people in their 20s today will never own their own home and will retire unable to afford rent in their retirement. A falling birthrate that means that working-age taxpayers will need to pay ever-bigger sums in tax to support the health and care needs of an ageing society.

Rachel Reeves is doing the best she can in the circumstances: raising taxes to increase spending on public services, and borrowing more to kickstart growth. The problem is that, while the extra money for the NHS looks good on paper, it’s around a 4% real increase in health spending a year for the next two years – only in line with the average yearly increase the NHS has had from its inception until 2010. It will stop things getting worse, but is it enough to drive radical improvements? And the extra investment Reeves is planning will take longer than an electoral cycle to boost growth: the Office for Budget Responsibility thinks it will add just 0.14% to GDP by 2029. Donald Trump’s presidency – especially if he launches a global trade war – is likely to make the growth and living standards outlook even worse.

It feels a bit like we are in a political doom loop: the financial crisis broke the happy spell of growth powered by the City, rising house prices and easy credit, and paved the way for years of stagnant living standards. Populist Conservatives promised to fix it all with Brexit; when the manna didn’t transpire, they were kicked out of office. Now Nigel Farage’s Reform lurks in the wings, waiting to reap the benefits of further disaffection and anti-politics sentiment if Labour doesn’t meet voter expectations. Things get tougher and populists do better.

Labour has to find a way of breaking this cycle if it is not to go the way of Harris. As the thinktank Labour Together has argued, that is partly about being laser-focused on delivering as much as it possibly can of what matters to most voters, and not getting distracted with “pet projects”. Reducing NHS waiting lists and reducing the cost of living are top of the list.

But I also think it has to find a different way of communicating with voters. The Conservatives overpromised and under-delivered. There is a danger Labour finds itself in a similar bind in four years: having promised the country it would deliver growth and fix the public realm, it simply will not have enough to show for it. Everywhere you look there are tough trade-offs, and little sign that the economic boom of New Labour’s first decade in power, which would make this problem go away, is going to materialise.

I wonder if voters would end up respecting ministers more if they found a way to be more honest about how difficult things are, and how the solutions have to be long term, in a way that isn’t simply about blaming the last lot and saying you’re the fix.

That’s undoubtedly a tough message to communicate but, unlike the other political pitches out there, it has the advantage of being the truth.

• Sonia Sodha is an Observer columnist