I think our biggest problem in Canada is total addressable market is small.. We're 40M people (compared to what, 350M in the US, and 900M in the EU), and we're directly next door to the largest startup economy in the world.
So not only do we have fewer customers, we're competing against an economic juggernaut that shares our broad business rules, our culture and language (with one exception) and can market to us through all our media channels with very little friction.
So unless you're in health care or some other regulated field that a US startup can't just expand into easily, it's a tough go.
There are a lot of "odd" things that happen to non-US citizens businesses that no one likes to talk about in public.
Indeed, if you are a Canadian Business getting market traction: the common scenario is acquisition by a US firm, or utter destruction by policy shifts and replacement by an opportunistic competitor. =3
Israel, like the parent poster said, is even smaller. I don't think an Israeli founder would have trouble moving to the US if they wanted to.