>>Seriously, is there any limiting principle?
>
>Yes, the money is taxed each time it changes hands.

Could that be one of the reasons there are so many middle...persons invented, and sometimes made mandatory? I remember farmers in some areas are forbidden to sell to anyone but wholesales. In some places they had to fight for special licenses to sell the produce (and wine and fruit and cheese) to visiting tourists. Or why is it so hard to sell/buy a house without an agent?

OTOH, various swaps, options, futures and other papers with funny names aren't exactly taxed each time they change hands, but only periodically, when decided which of the earnings are long and which short term investments.