You need people in society earning various incomes of 40,50,60,70,80,90...150,160,170...200,210,220k per annum as they live in different homes at various distances from desirable centres (be they cbd or suburban hubs etc) and thus have differing borrowing capacities (or rent paying capacities) to live in the range of homes and apartments that people live in across the country.
With ever increasing incomes come ever increasing household costs (rent/mortgage the largest).
If cities were all like old communist centres with the same exact housing situations then incomes could be the same.
I earn twice as much as my best mate but my mortgage is twice as his. Other costs ( entertainment, communications etc are identical basically).
My brother earns 4 times as much as me but he lives in a very desirable multi million dollar home (but again with mortgage to match).
With ever increasing incomes come ever increasing household costs (rent/mortgage the largest).
If cities were all like old communist centres with the same exact housing situations then incomes could be the same.
I earn twice as much as my best mate but my mortgage is twice as his. Other costs ( entertainment, communications etc are identical basically).
My brother earns 4 times as much as me but he lives in a very desirable multi million dollar home (but again with mortgage to match).