Legal immigration is the reason silicon valley exists. Ask Mark Zuckerberg why he moved Facebook HQ to silicon valley. It is because that's where the engineers are. If legal immigration wasn't a thing Zuckerberg would have moved considerable number of jobs to places like Beijing, Bangalore and St. Petersburg, because that's where he would have found software engineers.
Canada, already a major center for AI innovation, will be the new silicon valley.
Edit: s/H-1B/immigration/g because the exact visa doesn't matter.