Actually, it's not unions are bad, it's contractors are bad. Alon Levy's general thesis is that the Anglosphere (especially the US) stratospheric construction costs are mostly due to the Anglosphere-centric trend of contracting the design and planning of major public works constructions to outside firms, leaving the public agencies inept and incapable of properly evaluating how competent they are at actually managing their budget.
Anglocentric? Lemme tell you something about the new Berlin airport...
This problem happens all over the world. Construction is becoming more complicated per se. Buildings of the 1950s were much simpler to build. A modern "smart" building where doors have their IP addresses is basically an industrial-sized robot with a lot of moving parts.
Thats a good point, the other side of "regulatory capture" is having regulators who are so distant from the field they regulate that they aren't competent to regulate it effectively.