However, the previous bridge, presumably also built to Canadian standards, held up for half a century and was still working (albeit apparently not looking great) when they ordered it replaced.
It's a bit like here in US some construction companies will advertise they "build to code". That sounds scary to me, as all I hear is they would really like to cut corners, but it's those pesky building codes getting in the way.
Relevant illustration: https://xkcd.com/641/
Construction companies and contractors make money building things. An estimate, quote or contract for whatever work is being done typically includes a profit margin on materials, labor and anything sub'd out. If anything they want code that specifies everything be grossly overbuilt.
Not really. Nice construction is generally not valued highly. Builders construct to code because higher R-values, better house wrap, pressure treated cladding, etc. don’t really raise the sale price of the house. If you’re talking about multimillion dollar custom homes, sure, this stuff starts to matter, mostly because the people buying multimillion dollar custom homes will sue you for only building to code because they expect better.