I cannot say for how it is for other companies, but for the tech company I work for it was the immigration and visa mess that pushed us to move all of our operations from the US to Canada. These are not call center jobs either, they are good high paying development jobs, from our architects to junior developers.

The United States has made it too hard and slow to get the visas we need to conduct business. We sell our software online, we have customers all around the world. When we need to get the right employees and customers in one location to meet, we can do that in Canada. The United States, starting around 2016 and getting worse from then, there just became too many random work permit denials and extra hoops to jump through.