Quote from texrex2002:
Good post, but I think this last paragraph may be misleading. In the case of the grocer getting a dollar and then passing it down the line, it is the same dollar that transacts 7 times (that doesn't count as $7 worth of activity).
What (I believe) actually happens is that the grocer, the supplier, the packager, the farmer, etc., take a portion of their profit from the transaction (say 10% of their 15% profit, or 1.5% of the transaction value) and put it in the bank. the bank then lends out 7-10x the deposit, and THAT is what causes the money to multiply. Note that the original dollar doesnt make it very far through the chain, since every party takes a profit.
In parallel, the 90% of the 15% profit that is not saved by the grocer is likely spent on other (non-primary) goods and services that each then spawn other streams of profit-taking saving and re-spending.
It might be interesting to think about whether the type of good the $ is spent on makes a big difference in the length of the chain and the flow through of the original dollar. Spending it on a Supercomputer involves a huge string of suppliers, credit, salesforce & other overhead, whereas spending it on a ... I don't know, painted pebble at a trinket shop on the indian reservation has less of an effect. But then again, the profit margin is much larger on the latter transaction, so if the profit is then in turn spent on a tractor payment (or at the liquor store...) it starts it's own chain quickly...
I posit that the last paragraph may be total BS; was just musing...
Actually, truehawk described a complex urban economy quite well, and your musing leads you to the same place.
In a big industrial city, most of the business transacted is between businesses. The retail end that actually contacts the consumer is quite small, in comparison.
For instance, Mayor Bloomberg of NYC's company makes the majority of its money selling its goods & services to big financial firms. Only a minor part of its business involves radio, TV, and the web, and that's the only part the ordinary consumer would see.
On a rural Indian reservation, the chain would be much smaller, and the part of the economy in direct contact with the consumer much larger.