The new trade agreement does set the rules of the road at kind of a high level, but there are all of these small differences.
For example, how do you test a product? Think about automobiles. Think about any product you have to test for health and safety. The small differences still exist between the United States, Canada and Mexico, even in the new trade agreement. Those small differences, absent an effort to have mutual recognition, really end up costing a lot of money.
To give a car example—and I'm making this up; this isn't an actual thing—you might have to crash test a new car at 60 kilometres per hour in Canada, and in the U.S. that same car, made in both Canada and the United States, is tested at 65 kilometres per hour, and it costs $1 million per vehicle, or something like that, to test it. You don't get an increased benefit in safety, but you have this small difference in how you have to certify something. It could be electric wiring, food, medicines, etc., anything that's manufactured.
All those differences potentially still exist, and companies either choose not to go into another market, even if it's right next door, or spend a lot of money trying to comply with small differences that don't enhance safety. It's still there.