The good laborers are union workers, which drives the cost up significantly.
Profiteering from subcontractors and suppliers is the issue. All of these bids are public, this isn't exactly forbidden knowledge.
Union labor is really expensive. It cost my neighbor who is part owner of the SF ferry building wine shop, over $8K to install a TV set because it had to be done with union labor. And get this, he was not allowed to install it himself because of union rules.
I have another neighbor that works as a location scout for movies and commercials. He says all filming in SF has to be done by union workers and its much more expensive than filming outside SF.