[mirkules]

Unfortunately, you can't just erect 4 walls and a door, and call it a day. The problem you quickly run into are building codes.

You need to think about electrical codes, HVAC, accessibility, fire codes (sprinklers, flammability of materials, etc), evacuation planning, etc. In California, there's even a rule that at least half the outlets in an office area must be motion controlled.

Not saying I don't agree with you, just more things to consider about the complexity and, ofc, the cost of doing things like that.