The city planning of Harappa?

Harappan city sites, including Mohenjo Daro, Harappa, Kalibangan, and Surkotada were having large gateways at various entry points of the city. These gateways are seen even in the inner fortification areas also. At Dholavira, a fallen signboard was found close to the main gateway.

Explanation:

i believe the answer is: returns on investments, no wages

people who belong in upper class society would most likely get there by obtaining multiple source of income, which a certain percentage of ownership for businesses. since most of them are job creator, they would most likely get their money from profit, not wages.