[thaumasiotes]

It's an interesting refutation. The author explicitly claims the following:

1. Construction unions in New York, specifically, cause horrific and unjustifiable cost increases.

2. But unions in most of the country aren't in New York, and don't have the same power that NY unions do.

3. The problem is that New York is responsible for a lot of construction, and more sensible areas unthinkingly copy New York's awful, union-driven policies -- those other areas don't need to do things New York's way, but they don't have enough construction experience to know better.

The author goes on to say that union-busting politics as they exist in the US won't solve the problem, but obviously believes that unions are responsible for significant parts of it. (And in fact says in so many words that in the absence of particularized US politics, union-busting would be somewhere from neutral to productive.)

An immediate implication is that if you're worried about getting things built in New York, you should be trying to break up the unions there.