Earlier quoted context omitted.
Population of Berlin has hardly changed in the past 30 years, it grows at an annual a rate of like 0.2%. How is this madness possible? Edit: There were 3.5 million residents in 1993. It is projected to reach 3.6 million residents in 2029 [1] It's got to be something to do with financial markets and foreign investment 1 - https://www.macrotrends.net/cities/204296/berlin/population
Even if the population doesn't change, if more purchase power moves in (e.g. struggling artists move out, software developers move in) the market will go up. Also, Berlin was an odd place compared to other cities in Europe, when it comes to housing. Looking from the outside it seems like it was due for an upwards correction after 3 decades of pretty low rents since the fall of The Wall.
I don't understand what you mean or how it relates to supply and demand.