I appreciate the thought, but Canada has preferential hiring for citizens, and can’t begin to accommodate the thousands of out-of-work federal scientists we have, let alone all the academics looking for an exit. The brain drain will sadly be due to people leaving science, not leaving the US.
Academia is only one route - I've worked in both public and private sectors - there are opportunities as the boomers age out.
I have family in Norway who keep saying that if I get fired from my federal scientist position that I should go there. Even if that were possible, I’m not ready to give up on our country yet.