Because the world runs out of quantum leaps at times.
In theory we can 3d print houses now, but those are not more useful than a stick built house. They are very easy to change and repair which a feature most people like. The building wraps these days have rather insane R values and do a good job insulating the house. And most houses have some kind of blow in for insulation.
> The building wraps these days have rather insane R values and do a good job insulating the house
Building wraps have almost no R-Value. The basic function of building wraps is to keep water out, which is why they are called WRBs (Weather Resisting Barriers). Some higher end ones also block air infiltration, but those aren't used very much.
For example, staple up house wrap doesn't block air the way it's typically installed, whereas fully adhered wraps do a much better job of that.
Some sheathing systems (not house wrap) like Zip-R have insulation value, but not "insane" by any means. The maximum R-Value Zip-R gets you is 12 (at a big price premium compared to alternatives), and the code minimum for 2x4 walls is 13.
In many climate zones that experience both extremes of heat and cold, it makes a lot of sense for homeowners to exceed code minimums for insulation, although it makes less financial sense for production builders who are trying to minimize their build costs.
In theory we can 3d print houses now, but those are not more useful than a stick built house. They are very easy to change and repair which a feature most people like. The building wraps these days have rather insane R values and do a good job insulating the house. And most houses have some kind of blow in for insulation.