I take it then, that you are in favor of free trade? Productivity is great, but ultimately you need consumers to buy what is produced. If you can send the non-producing consumers all to Quebec and still get them to buy your stuff, great.
You are throwing in additional factors, but you aren't debunking the population/economy correlation.
Read the first paragraph of post 67. The second was a form of humor. The first does debunk the link between population growth and economic wealth. If this were true, then India and China would be the most wealthy nations on the planet.