what are the assumptions that get us the result of real estate prices in financial centre cities increase over the long term?

Yesterday I argued in financial centre cities, the real estate prices will increase over the long term. However, it involves some pre-existing assumptions that I did not explain yesterday.

First of all, the world economic performance has an increasing trend. This is important, because if the global economy is shrinking over time, then the phenomenon of more resources being attracted to financial centre cities will not occur, thus the real estate prices will not be likely to increase over the long term. The second assumption is we all stay on the earth. If we can travel across planets, the geographic picture of the world economy changes and some financial centre cities will lose their importance. The third assumption is there is an inflation in the world economy over the long term. Although we assume an economic growth over the long term, I still think we need the assumption of inflation, as many economic theories may be right at the moment, it does not necessarily mean they are right in the future, growth may not necessarily mean inflation in the future. If we cannot have an inflation over the long term, the real values of real estates may still rise but the nominal values could decrease over the long term.

However, if the existing financial centre cities attract almost all available resources around them, they will compete with each other. Although they are already competing with each other, the level of competition will increase over time, due to the development of technology, the need for multiple financial centres is less and less significant, eventually there could be one financial centre that absorb all resources from other financial centres. In this case, the one survival financial centre could an enormous increase in its real estate prices, while others will lose in the battle and the real estates will slump.