In a few months/years, students from India and China going to US for grad studies will slow down, and most of them chosing Canada over US.
In a few years, if US continues its systematic and unfair ways of keeping citizens of India and China from immigrating to US, and Canada continues its policy of courting immigrants, you'll see a culture of entrepreneurship growing in Canada too.
Meanwhile, these startup founders often come back to Canada after getting their startup off the ground in the US... to create a Canadian "engineering branch office"—i.e., to hire tech talent at the cheaper Canadian going rate. But, of course, this only happens for startups that manage to get to a stage where they need whole offices of additional tech talent—which is not most startups.
Given this dynamic, I wouldn't expect increasing the number of available developers would do much at all. Now, if you could come up with some way to keep entrepreneurs from moving to the US, that might help...
Canadian policy was always much easier than US for immigration. I wonder then why Indian/Chinese did not go in much larger numbers to Canada as compared to US.
They did, and they still do:
Canada's percentage of foreign born population: 20.6% [0]
US's percentage of foreign born population: 13% [1]
[0] http://www12.statcan.gc.ca/nhs-enm/2011/as-sa/99-010-x/99-01...
[1] https://www.brookings.edu/blog/brookings-now/2013/10/03/what...
1. there isn't much of a culture of entrepreneurship;
2. there are few VCs, and they're pretty much all hyper-conservative, to the point that they may as well be banks.