First, they are already solving the demand problem:

https://www.marketplace.org/story/2025/09/17/top-10-of-earners-make-up-half-of-us-retail-spending

The very small group of people with "important" positions in corporations will still be allowed participate in the wealth and drive demand. Everyone else will be forced to buy basic products like food and water at crazy prices basically giving away all income back to the corporation. Some tariffs, couple of wars and annexations will make sure they are not losing money.

You're right about the office space property values. They will most likely not convert it into apartments. Better solution is to just allow workers to sleep under their desks. You get to keep your office space and workers don't have to drive. You wold obviously have to charge them some rent to cover the energy use during night but it wouldn't be that high. At first.