When we go back in time, we worry about changing the past. But we expect this person from the future to tell us all the stuff so we can fuck around with (for them) things that already happened.
I think that a lower price for the rent translates into a lower valuation of the property. So an empty apartment at $2000 a month is still theoretically worth more at sale than a rented apartment at $1500
The objectively real world may be separate from and indifferent to sense perception, but sense perception isn’t indifferent to the objective world. Sense perceptions are caused by an interaction of our sense organs and the world. Surely from repeated patterns of sense perception we can draw some correct inferences about the external world?