But the point Marx is making is that there is a division of labour, but in a commodity, capitalist economy our mutual dependence goes unrecognised. In the 1920s there was a well-established worldwide division of labour, in which the USA produced most of the world's cars while Malaysia specialised in the export of tin and rubber. We need tin to make solder joints and for various other uses in car production. It's even easier to work out how much rubber goes in a tyre. But under capitalism nobody makes those calculations - that would be the way in a planned economy.
Nobody knows how much tin or rubber or how many cars the world needs.
In a global economy dominated by commodity production individual capitalists plough their lonely furrow, concerned only with the making of money. But when the car factories started laying workers off, and by December 1929 were only churning out 92,000 cars, that was bad news for tin and rubber workers in Malaysia. The little local difficulty in Detroit became a global crash. That is what credit does - it generalises local problems as well as it generalises local prosperity. It drops us all in the same thing together, whether we know it or not.