Assume that income is exponentially distributed.
Assume that given a real-world function x, goods and services g that achieves that function are log-normally distributed.
Consider an activity domain. An activity domain is a set of functions such that the execution by an agent are highly correlated with each other; the purchase of goods and services that achieve this execution by that agent are then highly correlated with each other as well. Consider a median expenditure m which is the median amount spent on goods in an activity domain by one individual.
Consider an agent that participates in multiple activity domains. We can presume that there exists a number m, such that for most activity domains, the agent spends lower than median if the median expenditure for that good is greater than m, and the agent spends greater than median if the median expenditure for that good is smaller than m.
Agents with lower incomes are excluded from activity domains with high media expenditure.