I think he is alluding that high rent leads to wealth concentration. A lot of salaried people can invest a tiny bit in a much larger variety of interests than a

I think he is alluding that high rent leads to wealth concentration. A lot of salaried people can invest a tiny bit in a much larger variety of interests than a few wealthy, or choose to work on something less profitable while still making rent. These investments by a lot of people will at some point lead to unexpected value creations that increase GDP. At least that is the tenet of a consumer and market economy.