TLDR: lowering the rent would create a direct problem for banks to convince investors the building is worth more. And since they've already given the money of the investor away (usually to construct the building in the first place), effectively the bank would have to pay back the difference if they did this.

So it's a choice between honesty and profit towards investors ...

Oh and obviously the "solution" is waiting for inflation to change the price of the rent effectively. So the real fix is for government to take the initiative and start paying people (by now, a lot) more.