Britain's big supermarkets are in trouble. Tesco's share price has halved in the last year, Morrisons has begun a price war with Aldi and Lidl, and Sainsbury's CEO Mike Coupe says: "The supermarket industry has changed more rapidly in the last three to six months than any time in my thirty years in the industry."

There's an obvious cause of these troubles. Six years of falling real wages - with maybe more to come - have forced shoppers to become more bargain-conscious and to shift to low-cost stores. This shift is quite consistent with Mr Coupe's claims that things are changing rapidly now, because consumer spending is a matter of habit, peer effects and social norms (such as the erstwhile stigma against Lidl), and these can change slowly at first but them quickly.

This, though, implies that the wage squeeze isn't just bad for workers but also for at least part of capitalism. Which in turn supports the idea that wage-led growth (pdf) would benefit not just workers but bosses too. Perhaps, therefore, the interests of capital and labour coincide. All would benefit from higher wages.

Which brings me to a puzzle. Very few commentators on the supermarkets' woes are drawing the inference that the TUC might be right: Britain needs a pay rise because falling wages hit businesses as well as households.

Why are they not doing this? It could be, of course, that it's mistaken. Just because some capitalists would benefit from higher wages it does not follow that all would. However, whilst there has been a debate about wage-led growth in economics blogs, this debate, AFAIK, has barely entered media or business circles.

I fear there's a reason for this, pointed out by Selina Todd in The People: The Rise and Fall of the Working Class. Workers' interests, she says, have always been regarded by those in power as a sectional interest opposed to the national interest. Even the 1964-70 Labour government, she writes, "regarded workers' rights as being distinct from the 'rights of the community'."

From this perspective, the failure of "business leaders" to even consider the possibility that wage-led growth is in most people's interests might be an example of a path-dependent belief - an idea that lingers on even if it has outlived its usefulness.

Or is it? Perhaps instead what we are seeing here is what Kalecki called the "class instinct" of capitalists. This tells them that even if higher wages do benefit capitalists in the short-term, they are to be resisted because of their longer-term dangers. After all, if we start empowering workers, where will it lead?