I'm so tired of hearing this complaint.
This is often stated as a problem, but the simple fact is that people can move to almost any other developed country and make as much or more than they would make in Canada.
Canada doesn't have a problem with talent exodous, they have a problem that Canadian employers are stingy and then complain when all they have left are people willing to settle for half they'd make in the US, or 2/3rds of what they would make in Europe. [0]
Here's a free tip for any Canadian employers reading: want to have Silicon Valley level talent at your company in Canada? Open your wallet. People are more than happy to stay in Canada if you pay them what they're worth.
[0] Anecdotal evidence, I'm Canadian, living and working in Europe. I make as much as people 10 years older than me make in Canada. Taxes are similar, cost of living is similar, social benefits are similar, and 5 weeks paid vacation (real vacation, not PTO).