I'm not sure what you mean by artificial land growth limitations. If you're talking about building height or city size limitations, Vancouver certainly has height restrictions, and it's surrounded on all sides too (UBC, Burrard Inlet, Burnaby, and the Fraser). You could build more outside of Vancouver proper, but then executives wouldn't want to live so far.
There's probably a large societal aspect to this too; the gender imbalance stands out much more than ethnicity, in my opinion.
Note too that each country can only send 6 people, and Asian countries (China, India, arguably Japan and South Korea) have a much larger pool to draw from, although this doesn't explain the prevalence of Asian-Americans on the USA team.
It's the bigger home with a bit of green space that they can't afford. You might be able to squeeze in a kid or two anywhere, but as you said, it wouldn't be ideal. I'm sure they're considering the trade-offs.