What could be the possible downside of investing in big cities?

Land is extremely expensive in big cities. Therefore, the land component in property
prices in big cities is very high. As downtown areas of the city become more
expensive, buyers have to move further and further away to the suburbs and
peripheries to buy property that fits their budget.
Moreover, population in cities is increasing at an alarming rate and demand for
housing is directly proportional to the increase in population. This is a reason for
properties becoming expensive in big cities.