The real estate costs don't go away, they just are paid for by the worker instead of the employer. Now you need to either dedicate square footage to an office setup, or get a bad back working from the couch or the bed or other common home furniture ill suited for long work hours. Maybe you legitimately don't have room in your apartment for this, and now need to invest in another bedroom. Maybe you need to buy faster home internet, or move apartments entirely due to a lack of ISP choices at your address. I've never heard of a business offering a stipend or remote assistance subsidy of any sort to their workers to cover any of this, from whatever great savings are reaped from saving on real estate costs.

I think there is a happy medium, where maybe offices cut back to about 25% capacity or so. People would instead drop in and work like a university library. You could go there and print stuff out if you didn't have a printer at home. If your laptop blew up, you could go there and get a replacement from IT. If you preferred, you could rent out a substantial desk with several monitors and a good chair if you didn't have the space at home, or focused better in that environment. You could schedule in person meetings with your team in a well appointed conference room if you wanted. You could host social events. Maybe even a gym or childcare facility. I think that's my ideal for the office environment going forward: less a sweatshop and more a clubhouse.