Tha answer is yes.  Just look at our historical standard of living and you will see that we are better now than we were in 1970, or whenever we were at 20 million people.  The best way to increase GDP is to allow more immigration, particularly of people with the skills that we will be losing over the next 20 years.  If we don't replace retirement we will have too small a working base to support our social programs.  I also support infrastructure, but I think tht's a less important route to better GDP and a tougher one to boot.  Great opposition to individual projects such as the KM pipeline, or the Site C dam.