You will need additional staff at Buffalo to detach and attach cars. At present there is none such. That will be significant additional labor. In addition there will be one time cost of constructing a siding with shore power facilities for storing the cars. Also, there will be ongoing additional cost of servicing the cars stored there. That is just a SWAG. I am sure if Thirdrail7 was around he would add a few more items that I have not thought about.
I think Americans are looking for the impossible. They will either have to accept something akin to Sections, perhaps with more robust night time enclosures that can be taken down during the day time, or they will have to accept Couchettes. Absent those they will just have to live with Roomettes. Maybe something like the Duplex Slumbercoaches can be tried again as an alternative, but that is more complex internal furnishing, though could be designed as modern modules perhaps using materials available today that were not available back then. No need to try to fit a commode and sink in the individual cubbies.