Even if the cost to launch would be way cheaper, that weigth allowance would be used for useful stuff like laundry machines, more "sterile" modules as you call

Even if the cost to launch would be way cheaper, that weigth allowance would be used for useful stuff like laundry machines, more "sterile" modules as you call them for more research, and potentially for industrial applications like factories to build low-gravity-only components and low gravity biomedical applications. Your vision is useful for tourism and little else.