If I’d said to you last year “Hey! I bet Canada is going to join the EU! No, of course not as charter-violating full member, as a newly invented ‘associate member’!” You’d probably have said “That’s both crazy and oddly specific, the chances of that have to be approaching zero”.

That’s why.

Yes but also "associate member" is, despite specificity, less surprising than full membership would have been.

Same as economic gravity meant that Brexit didn't disconnect UK from EU it only made trade harder, neither this kind of deal nor full membership can be much more than a band-aid for Trump's BS, it won't fully compensate for the harm he and his administration are doing to Canada.