Circular Transactions mean something else and are orthogonal to this conversation.

That said, the reality is that the 70th percentile of household income nationally is a little over $130K [0] and the US is a country with a population of around 341 Million people.

Therefore, you can have a self-sustaining consumer market with around 100 Million Americans who are members of households earning above $130k a year - you would end up with a significantly larger TAM than targeting the bottom 70%.

Most skilled (SWE, Accounting, Law), semi-skilled (Automation Engineer, Mechanic), civil service (Police, Teachers, Local government employees, Military), and union employees all marry people within this strata and remain in that strata.

[0] - https://dqydj.com/household-income-percentile-calculator/