What is unsaid is when a Canadian worker in US gets laid off or just decide to leave (s)he is just moving in first world. Apart from less pay, living standards are pretty much same in US and Canada. But if Indian worker gets laid off it will be drastic change in living standard by going back.

Even very high Indian salary would not buy that US lifestyle. Of course many people will like to couch that fact as having friends' circle in US, kids schooling etc makes it difficult to relocate.

You missed my point. It is not about poor countries. Indian's and Chinese will not have job mobility for decades. That is the reason, last year, 80%+ of H1B visas went to Indian/Chinese nationals.

I didn't miss your point, I just don't agree with it.

I suspect 80%+ of H1B visas go to Indian/Chinese nationals simply because they represent a similarly large proportion of STEM graduates interested in emigrating from their home countries.

TN visa restrictions are much less onerous to an employer and employee than an H1B. Similar culture and less restrictive language barriers are also benefits that might lead an employer to hire a Canadian. I would suggest that the first point is the likely culprit for the number of Canadians employed in the US.

If you're Canadian why are you getting a H1B? Get a TN. It's simpler, faster, and way less onerous than a H1B.

Can't get a TN for investment banking, it's not a supported occupation (one of my friends had to do this).

Similarly for a few other occupations. And, of course, some want to hedge their bets in case they do want a green card in the future.

It's not dual intent for one thing. I have a TN but my company put in for H-1B for me so that I could switch and then have the option to get sponsored more easily if I decide I want a green card.

TN you can do it, but it's messier.