I don't know what it's like in Vancouver, but I have lived in Massachusetts and there it's not really a union issue: the corruption is equally present in, say, government (e.g. until recently there was a whole county all of whose land had been taken away but that remained solely so jobs like sheriff, bailiff etc could be handed out to relatives in cronies. Anything with a large flow of money (e.g. the Big Dig) gets openly looted. I've been told the same is true in Chicago, but I don't know directly. As far as the unions go, indeed, the lack of seriousness about the work is how, for example, the Ted Williams tunnel killed people, with no repercussions.
OTOH what passes for corruption in California, where I live now, would make an east coast politician laugh. Certainly in the trades (welding in particular, but all sorts of construction I needed) the quality of work was top notch. And why not? In construction, at least, there is no reason to use union if you don't want to and most don't, which leads to the the shitty quality of residential construction (there should be more of it but that's another issue).
Perhaps one thing is regulation. We once bought a pressure vessel that arrived with a small ding (if bad, it's an opportunity for an explosion). We called the pressure vessel unit in Oakland and someone arrived in 45 minutes which means he'd dropped anything else and and hopped into his car as soon as we hung up the phone. Even before he arrived we got an annoyed call from the mfr (as it turned out all was well...but the pressure vessel unit wanted to see for themselves). While he was there we showed him a piece done by a former contractor who had not been able to produce the union tickets. We had fired them because the work was safety critical (high pressure steam is no joke) and the contractor was suing us. One look at the piece and he yanked out his phone. Let's just say later that day the contractor's lawyer couriered over a document cancelling the lawsuit, a cashier's check for money already paid, and a request that we not countersue. Those guys are not fucking around.