The USA attracts talent, and workers.
Those that can't get into the US but get into Canada and are reasonably talented, who don't have family ties - eventually go to the US. Two of my staffers, one from India, one from Jordan, just did this. For them, Canada was a temporary layover for a few years until they could go stateside.
Canadian wages are considerably lower than the US for 'talent' so generally, people prefer to go to the US.
Canada doesn't have very many true product, engineering, design jobs wherein the outputs are developed on an international scale, not a lot of things are really 'made here'.
On the high end - Canada imports doctors, software folks to do CRUD, ane engineers that never get to do engineering. One specialization is teaching and research for University, some number of profs are brought in.
But mostly - it's people with education who will never get to use it, and a lot of people to work in retail, coffee shops and Long Term Care homes.
Edit: after reading, this sounds very cynical! Although it is to some extent. Migrants to Canada in the economic class generally have education, like a Uni degree, though this is an only necessary one in the family, not necessarily the spouse, parents, obviously not the kids. Skills are often not very transferrable, and there are surprisingly few jobs wherein one can jump right in with 'technical knowledge' of some kind and Canada does not have the high-tech industrial base to support the need - Canada is almost last among OECD nations in terms of R&D investment, not because of the lack of R&D among individual companies, rather, the lack of the kinds of companies that actually do R&D. The Uni system is very good, tons of good research, but the commercial bits don't happen in Canada.