All of which begs a question: if our rare giants are doomed to fall and our startups are fated to exit outside of Canada, what sort of tech sector do we really have? More important, do we even need a tech sector?
Bad premise -- neither of these are foregone conclusions.
Plenty of "giants" from the past two decades have fallen on both sides of the border. There's no reason to believe a Canadian "giant" is "doomed to fall".
As for our startups being "fated to exit outside of Canada", there are plenty of examples of companies who are growing fast and seem to be in it for the long run (Shopify, FreshBooks, HootSuite, Wattpad). Some of these companies may ultimately exit to a foreign buyer, but each startup launched and exited is another shot in the arm for our burgeoning startup community, and I suspect that an increasing number of Canadian companies will be sticking around as this community grows.