I never claimed that it was impossible, but that there are fundamental differences which makes squirting out thermoplastic out of a small nozzle quite convenient, and concrete out of a huge one, quite problematic.
The thing you wrote about lintels, and some of the stuff I've seen about reinforcement with rebars on the link you provided, which all need to be done manually make the process labor intensive, the issue 3D printed building were designed to solve in the first place.
I'm honestly puzzled by some of the techniques, where one guy is spraying shotcrete at a rebar structure - what is being 3D printed at this point?
And the resulting building will be a concrete house - not necessarily the most environmentally conscious, beautiful, energy efficient, best insulating material.
There's one overhang solution in my previous link, the more recent videos about printed houses with windows use a different, traditional, solution: lintels.
As for reinforcement, I can't say I really deeply understand the Wikipedia page "Reinforcement in concrete 3D printing", but it is quite sizeable and lists many things:
https://en.wikipedia.org/wiki/Reinforcement_in_concrete_3D_p...
To be clear, I also think 3D printed concrete is a case of throwing buzzwords at problems rather than a good idea, but not because it doesn't work, rather because it produces a merely OK result for what is the single cheapest part of the construction process — I can get a prefab shell of a house built here in Germany for €100k, but that turns into €550k when you add the land, preparation of the land, connecting utilities, wiring and plumbing, and interior plastering.