It was all going to script until the rich guy in the pinstripe suit said young people should “get off their arses”. I was in a television studio for Channel 4, trying to explain French economist Thomas Piketty’s inequality thesis to a befuddled audience. But something snapped.

Wages as a share of UK GDP have fallen by around 10 percentage points since 1973. And we’re now in the seventh straight year of falling real wages. That means, when you tell young people to “get off their arses”, they have a strong incentive to move into the grey economy. If wages stagnate, yet everyone with money can demonstrably make money in the financial and property systems, the logical thing to do – if you are an 18-year-old on the streets of a British city – is dodgy stuff.

When I pointed this out, the audience exploded. One man yelled: “We all have to do dodgy stuff. Wages are not enough to live on!” – and he reeled off a list of dodgy activities he had taken part in. On top of this, he insisted, the entire country is run by corrupt people on the make, so why should ordinary people do different? He got the loudest cheer of the night from an audience that had just been let into the guilty secret of modern Britain: we are poorer than we think.

If you’re earning £33k you are – well, where exactly? Numerous people we talked to on this salary thought they were in the bottom third of the wage-scale. In fact, in a single-person household someone earning £33k would be in the top third. And a £60,000 salary puts you in the top 10% of earners. We all dream of earning more, but throughout the western world, wage inequalities have widened and, since the financial crisis began, real incomes have stagnated. The bald truth is: low-skilled wages are clustered just above the minimum; only one person in three will earn more than £30k or its future equivalent; and as for a six-figure salary, it’s a dream only 2% or 3% of people are ever going to realise.

When it comes to the cause of growing wage inequality there is, typically, an argument between economists. The four likely causes are technological change, globalisation, cuts to the welfare state and our increased reliance on finance.

Technology can reduce our bargaining power by automating traditional jobs. If your job is being automated, any attempt to boost your wages by working with greater skill, or by taking advantage of a labour shortage, will be impossible.

Specifically, information technology tends to “hollow out” the semi-skilled occupations that were once associated with being at the high-paid end of the working class. In the vernacular, even when you have “got off your arse”, there’s very little upward wage mobility possible outside the public sector and the degree-educated salariat.

Globalisation – especially for an open trading country such as the UK – impacts in two ways: if cheap labour can move here and capital can move to where cheaper labour exists, the ability to defend higher-paid jobs goes out of the window.

The third factor, the size and generosity of the welfare state, is often said to correlate closely with wage bargaining power. The case of John McArthur, from Motherwell, illustrates how: having been placed with a firm on the minimum wage by a government job scheme, when the funding for that scheme ran out he says the Department for Work and Pensions forced him to work for the same firm for nothing. His bargaining power, to put it mildly, was reduced.

But it is the combined rise of lifestyles based on credit, and business models attuned to financial profit, that is driving wage inequality faster than all other factors.

Engelbert Stockhammer, professor of economics at Kingston University, last year crunched all available data on falling wage shares for 71 countries. He found that over a 10-year period, for the advanced countries, the biggest driver by far was this phenomenon dubbed “financialisation”.

It’s a complex process: first, companies become driven by the short-term demands of shareholders, or by debt-finance takeovers and their only option is to slash wage costs. Next the composition of the economy shifts – from the factories and heavy industry of the 1970s and 80s to the distribution centre and call-centre work that is common now. Trade union bargaining power is eroded – and this was the overt aim of both Margaret Thatcher and Tony Blair – and the current system of individual secret salaries and precarious jobs is imposed. Finally, to sugar the pill, you can live on the lower wages because credit is endlessly available. From mobile phones to new cars, to overdrafts, capitalism is now structured to turn every consumer into a financial income stream. Long before you bought your gym membership, the gym itself had sold the projected income into the financial markets, to be traded against other streams of interest.

When the entire system is based on credit, there is no incentive to call time on anybody. Though everybody railed at Wonga, which mis-sold credit to hundreds of thousands of the poorest people, nobody asked: who benefited? The answer was, of course, the other creditors of the poor: the buy-to-let landlord, the car-loan company, the bank, the arrears-collecting local council. The Wonga lifestyle is to borrow short-term to service long-term debts: financially illogical, but the system is stacked in favour of the lender.

There is growing evidence, then, that finance, not technology, is primarily driving inequality. That means it is not inevitable, but the product of laws and institutions, not silicon chips.

It feels to me as if we are at a tipping point in terms of attitudes to wage stagnation. Even those in authority are starting to think it is a major cause of stagnating growth. When the Bank of England’s chief economist sounds the alarm bells, as he did last month, you know that telling people to “get off their arse” will not be enough. We’ve constructed the economy so that the rich get richer. And if cuts to the welfare state drive inequality, as most economists accept, then current government policy will drive it higher.

The solution is easy to envisage – but distasteful to mainstream politics. It means generous welfare benefits, strong unions with institutional bargaining arrangements and less globalisation: less offshoring, less outsourcing, less temporary work. Who won’t like it? The financial markets, which have, over these past 20 years, destroyed the kind of companies that used to offer decent pay and stable jobs.

For 20 years that has been enough to take policies designed to reverse the falling wage share off the agenda. My sense, from the sheer outrage I heard among the TV studio audience, is that this could change.

Paul Mason is economics editor of Channel 4 News. Follow him on @paulmasonnews.

How Rich Are You? is on Channel 4 at 8pm on Monday 10 November.