No, they are exactly right. Former migrant and working-class districts have been turned into habitats for the rich and the upper-middle class. Lower and middle income groups are driven out of the city. (Not completely. After all, we need them to take a two hour commute to wash the clothes of the rich and serve them coffee.)

Also because big corps pay insane amount of money and most companies can't follow, especially in berlin, which is neither a tech nor a financial hub.

There isn't a single cause to that but these companies are definitely part of it. If no one could rent these flats they wouldn't be that pricey... There is a lot of affordable housing too, I'm in the process of looking for a flat and a good 30% of them requires a Wohnberechtigungsschein