This is extremely common in the Netherlands. Also very well sorted out these days. My parents' company used to assemble these. A specialised contractor digs and

This is extremely common in the Netherlands. Also very well sorted out these days. My parents' company used to assemble these. A specialised contractor digs and pours a concrete foundation for the walls and once those would be cured a crane, a loader truck and a crew of maybe 3-6 people would on average have a new house ready every 3 days (walls, floors, roofs, wiring, piping), 'ready' being very close to how they're sold to individual owners. A prefab house design will typically be replicated in several projects / cities, usually with a few customisation options. Different prefab factories have different levels of standardisation and automation. The prefab production lines I designed long ago for example used fully parametric designs to offer standard concepts sized to fit. At the time (~10-15 years ago) a novelty, by now must be pretty standard.