According to Bruce Garrioch, Trouba made it clear from the moment that trade talks ramped up that he wasn't interested in living in Canada, and given that all seven Canadian teams were on his no-trade list, he had the power to deny any trade there.
With a massive $8 million AAV left on his deal for this season and next, it makes sense why there weren't that many suitors for Trouba, but combining that with his denial of all Canadian teams, it starts to make more and more sense why there was a limited market.
At 30-years of age, we know what Trouba is right now, and that's a very limited, physical defenseman, so perhaps this wasn't the worst outcome for those teams, even if they are all in the market for major defensive upgrades.