I would point out that when the City of Hamilton was certified, the staff did a detailed analysis of contractors who were already pre-qualified to bid on carpenter-related work. They found that out of the more than 200 contractors only 17 were qualified now that they had to have a carpenters' agreement.
When the city put out its first request for pre-qualification on a large water treatment plant, it got no applicants. It took a year and a half.