Apart of the operational challenges mentioned in the article, of course, making it happen isn't trivial, it has costs as well.
It's not the small number of Chinese electric cars Canada will be bringing in. It's Canada's replacing a big chunk of US soy in return that has him really irked. Much of the world is fed up and pushing USA away, while Trump continues to aim at the low hanging excuse-fruit instead of admitting (or recognizing?) his failure as a leader. It took starting an illegal war and complaining nobody would join him to distract his people from all his other problems. Less than half of USA still believes him. The entire rest of the world does not.
He keeps saying he doesn't need this and that from other countries, and then panicking when the other countries agree and move on.