Although Singapore is outperforming our economy (on a per-capita basis), Canada is not. Why do you believe emulating them will get us Singapore-like benefits rather than Canada-like harms?
1. The Canadian economy is largely based on exporting goods to the US or exporting natural resources world-wide.
2. When the Canadian dollar reaches par with the US dollar, the benefits of US companies doing things across the bordering Canada rapidly evaporates. This means that economies like Ontario start doing poorly, while economies like Alberta and British Columbia that have natural resources to export start doing better (well, at least when coupled with an increase in oil prices.. because the tar sands become viable).
3. A lot of money comes into the Canadian economy through the entertainment industry. There are huge tax breaks in Ontario (specifically Toronto) and BC (specifically Vancouver) for doing things there, in addition to the exchange rate (when the US dollar is riding higher).
yummy: good question, and let me preface by saying I'm generally sympathetic to your worldview.
I think the answer is that this policy is pretty much directly guaranteed to increase the human capital and GDP-per-capita of the receiving country. Canada does plenty of other stuff badly, but if you've seen the latest Heritage ranking they actually exceed the US in economic freedom for the first time ever. With the exception of an enlightened, merit-based immigration policy Canada isn't doing many things right...but it is doing far less that is grievously wrong than the US.
I'd take even odds that once the pending true economic collapse happens (including devaluation of the dollar, tuition bubble pop, Euro breakup, et alia), that Canada will have a higher GDP-per-capita than the US within 5 years and certainly within 10. But this takes us far afield.
http://en.wikipedia.org/wiki/List_of_countries_by_GDP_(PPP)_...