They are mythologized in news, song, film and TV.

Try to recruit someone to Toledo, Ohio vs. SF with the same cost-of-living-adjusted-pay and there's no comparison.

California is a place where people 'want' to move. NYC has been branded as the 'centre of action' for almost a century now. Just the other day I was reading about how artists feel they need to be located there for brand purposes.

The only people who 'aspire' to move to a regular city are those in smaller towns in the immediate vicinity, i.e. in rural Ontario, Toronto is an 'aspiration' it's 'the big city'. (Also, Toronto is an aspiration for a lot of migrants worldwide but that's a different story).

SF and NYC have access to a global talent pool.

Toronto has access mostly just Ontario.

FYI I worked at a 'big name company' in Waterloo Ontario and it was really hard to bring people in, especially Americans for whom Canada it seemed may have as well been the arctic. Those few we did bring up, often kept their 'primary residence' in the US, or otherwise felt they were doing a 'tour of duty' and would otherwise want to go home.