You're assuming that the contractors will always be on premise. With covid-19 (and even before), most of these companies have established bases in Canada. The only obstacle has been management resistance to remote work. With covid-19, that's not going to be an issue.

What I'm trying to say is that just because h1-b's are curtailed it won't result in contracts not going out to these companies. The contracts will still exist because the rates are extremely attractive. The workforce will just be filled up in Canada.