Because canadians are risk-averse. Hence why only the banks have been continuing to make money; they even invest in each other to keep the risk-averse cycle going.
It's also due to, in the case of the Quebec government, nationalistic sentiment.
It's a difficult balance to strike - keeping and supporting high tech manufacturing, while trying to remain competitive. I think at the moment, the government intervention (blocking suitors and direct investment) is in fact doing more harm than good, but perhaps they know better - I have no knowledge of how competitive the C-Series really is or not.
The liberal party of Québec isn't very nationalistic, it's mostly that they have very deep ties to the Beaudoin family that has inherited Bombardier from their parents without having the competency to manage it. And our government is in the hand of corporations since we still have colonial institutions, so they spend our tax dollars on free loans that will never be paid back.
The canadians who want to invest in risky industries have more incentives to do so south of the border. Most of our population is within 100km of the american border, and it's pretty fucking easy to get a visa if you're about to invest money in the US.