Canada doesn't get lower prices because they can import drugs as individuals. They get such low prices because the Canadian government is the insurance for the whole country and has the negotiating power to actually get lower prices out of drug companies. Medicare part D in the US can't even actually negotiate for lower prices in the US!

Allowing import from Canada is just a bandaid to make it seem like they're doing something about the actual problem and will only work as long as we assume the supply of Canadian drugs can absorb both it's own demand and the US demand.

This is actually not true. Healthcare is a provincial matter in Canada, not a federal one, and there is no broad-based pharmacare program. Many Canadians have private insurance covering the cost of pharmaceuticals.

This isn't true, Canadian's have private insurance for pharmaceuticals that isn't a part of their broader single payer system for standard healthcare. As a matter of fact, the current proposed medicare for all bill, would go far beyond what exists within Canada in terms of coverage.

... until the supply to Canadians becomes affected, making the government impose export restrictions.

Drug companies might stop selling in canada entirely to protect US profits.

Drug companies only have any kind of exclusivity or advantage at the pleasure of governments. They can't go too long playing hardball or countries will just start ignoring their patents.

It's beneficial to both parties once that point is reached.