Another limitation is the transport capacity of each power line and each transformer (power lines and transformers don't care for the direction of the electricity, only for the amount of electricity).

For example if each house in a city would have 25A fuse and all the houses would simultaneously draw 25A, or simultaneously supply 25A the grid would collapse.

Usually the Diversity Factor for apartment block electric grids is around 35%.

https://www.geeksforgeeks.org/electrical-engineering/diversi...

https://ecalpro.com/compare/demand-diversity-100-apartments