The biggest cities dwarf the surrounding small cities monopolies craps more profit than combining a majority of competitors money follow the same pattern as an investor in venture capital you should not over diversify as returns are not normally distributed. For example, some companies will fail, more companies will stay flat and a few superior companies will potentially return ten times their initial investment. If graphed, it might look like an inverse probability flat. In reality, the investors should focus on the few superior companies that get exponential results