Not quite right. A single-layer masonry can insulate just as well as a multi-layer masonry. A multi-layer masonry with ETICS can be built more cheaply. However, masonry with ETICS can cause major problems in a fire, the plaster surfaces are more susceptible to mold and algae infestation, and the entire masonry cannot regulate nearly as much moisture as a single-layer masonry made of brick. The facade with ETICS is made of polystyrene and is therefore in no way massive. You can’t even attach a satellite dish or awning without special fittings; the window sills hang like shelves with a bracket on the wall... I don’t even know where to stop.
1-layer = wall made entirely of one material (e.g., brick 36.5cm) = gold standard (this is how grandpa used to build)
2-layer = 1 layer of one material and 1 further layer of another material (e.g., aerated concrete and polystyrene) = cheap standard (this is how we build today because being stingy is so cool)
3-layer = 1 layer etc. (e.g., brick / insulation / facing brick) = "Mercedes" but not necessarily better (this is how grandpa used to build when there was more money)
We build our houses single-layer with bricks. The advantage is the good moisture-regulating property, which no other material provides anymore. The wall thickness is standard at 36.5 cm.
There are various designs for better thermal insulation of the building envelope. The biggest advantage, however, is always the significantly better soundproofing. With a thinner wall, you have much less soundproofing.
What many builders unfortunately do not consider is: ETICS really has not much to do with soundproofing. But you can calculate a nice U-value (important for the rating of the thermal transmittance of a wall) and then feel really comfortable with that.
...just have a look on Google under "Wienerberger," "Röben," "Eder," etc. You’ll quickly find what you’re looking for. The question is, why do I even need ETICS?