The cost of the structure of a modern wood house is a tiny fraction of the overall cost. Most of the construction cost is in the wiring, plumbing, bathroom & kitchen fixtures, windows, flooring, etc. 3D printing doesn't help with any of that. In fact, wiring and plumbing is harder than in a wood-framed building, where you can drill holes in a few seconds.

Also, aesthetic zoning rules are super-conservative. You can't build an unusual looking house in most cities.