What you're missing is, at best, the tech to achieve this without actually needing the camera placed inside the room, will exist at scale in this century. At worst, it is already deployed in "hot" areas (areas significant to national security, experimental areas).

The question becomes how to control the inevitable proliferation of commoditized mass survelliance.

Privacy in the future will require a level of defense not available via common residential/commercial construction methods. Hell, even a SCIF eventually won't help..