'It is important to grasp the deep cause of the present crisis," wrote the American economist David Schweickart in 2009. "It is not the sub-prime lending nor the housing bubble that might have been reined in." Brilliant. I hate it when people blame sub-prime. Half the room thinks "this is a poor person's problem", the other half thinks "this is an American problem", and I personally start thinking about prime rib. "It is not Wall Street greed, nor their feckless 'innovations', nor even the reckless borrowing that has characterised almost all sectors of the economy," he goes on. "These factors have all played a role, but they are at best proximate causes." But if poor people aren't stupid and rich people aren't greedy, I don't really see where this sports match is going.

In fact it's going towards one of those graphs that Twitter calls "the most mind-blowing graph you'll ever see" – it won't blow your mind, but that's a good thing. You will need your mind. It simply shows the divergence of productivity and wages in the US between 1945 and the present day. During capitalism's "golden age", 1945-75, the (simplified) story is that wages and gross domestic product went in tandem. From 1975 onwards, wages flatlined and productivity continued to grow. In the UK, where neoliberalism moved more slowly and had, at least to start with, more effective foes, productivity didn't peel away from wages until 2003.

From here, the crisis proceeded as inexorably as the final tricks in a hand of whist. Wages no longer met consumption but the people at the bottom still had to consume, and those producing still needed them to do so. Lines of credit were extended, whether in the form of a sub-prime mortgage or a 0% credit card, and consumption continued.

This makes it a fairly pointless task, making a choice of culprit between the employers who drove down wages, the casino banks who took unintelligent risks, or the high street banks who extended credit with no thought for those they were lending to – all concentrating only on how to keep their own ship steady. They form a nexus in which they are all as important as each other.

The economist Ann Pettifor describes it as "cannibalistic capitalism". They consume their own customers. Then they wonder why their sales are so low. Then they use the severity of the recession as a rationale for treating people more harshly, and wonder why their sales are even lower. Never mind "unsustainable", this actively propels us into an ever-worsening situation.

The solutions to this will be large and manifold – they'll start with collective pay-bargaining, and an generalised acceptance that unions are not about angry men in smelly jackets but the mechanisms by which people who work exert any power over those who profit from their work. But before that can happen, or anything that this situation needs, a fundamental acknowledgment has to be made.

Wages in Britain are too low. We know they'd dropped away from GDP before the recession, but the situation has since become much starker. The Institute for Fiscal Studies produced research today revealing average pay cuts of 6% over five years. Given that workers would normally see 2% annual rises, this amounts to a gap of 15% between what they're earning now and what they would have earned without the slump.

Two related political slogans have been tailored for the purpose of denying this: the first is "reform benefits to make work pay"; the second is the false dichotomy between strivers and skivers.

You don't reform benefits to make work pay. You reform wages. The minimum wage is not enough to live on, even leaving aside the rate of unemployment, the rate of under-employment – people who would like to work more hours but for some reason probably related to withholding their statutory rights are on zero- or four-hour contracts – and all those cannibalistic stunts that particularly large large employers,, in particular, have adopted. This is a profound drag on an economy trying to get out of recession. Reducing benefits won't help.

The strivers versus skivers narrative is, overall, devised to build a scapegoat class for a situation that would otherwise seem senseless: how is it reasonable to work full-time and not be able to pay your rent? How is it fair that all the flexibility in the workplace must be borne by the employee and none by the employer, so that a supermarket worker might start each week not knowing how much money they'll take home?

How can a government lecture you on parenting on the one hand, and idleness on the other, from within a system where paying for childcare leaves many people's work income-neutral, and keeping your head above water will probably involve at least one parent not seeing their children at all? These are questions that are short-circuited by the spectre of a leech class, imbalancing the economy by actively refusing work in favour of benefits. But the sheer, grinding difficulty of life on a low wage cannot have escaped the notice of the people living it.

There has been a problem looming over the debate since the financial crisis exploded. The culprits are too large and too complicated, the solutions are too revolutionary and too violent – and above all, how do you gather opinion behind a set of ideas that are too intricate to explain? But this idea is simple: wages that people can't live on will drag a society into recession and hold it there, whether the state subsidises those wages or not.

Twitter: @zoesqwilliams