But, in my opinion, the basic insight here is that US companies pursued globalization and offshoring more than Canadian companies did, boosting the importance of trade to the US economy more than was done in Canada. When a company procures one slice of its value chain offshore, it does so to reduce costs.
The result is that the average productivity of the domestic operation goes up. This isn’t a productivity miracle; it’s simply arithmetic. US firms are more likely to be larger than Canadian firms. That means they tend to have more outsourcing opportunities.