[1] https://www.iflscience.com/health-and-medicine/medicare-for-...
What could happen is that Biden gets KO'ed by the disease, leaving Sanders the default democratic candidate.
Just as interracial marriage, womens’ voting rights, the legalization of abortion, same sex marriage, and the slow sweep of marijuana legalization and prison reform come eventually, this too will arrive. We’re just arguing the timeline, which is frankly insane we’re willing to wait so long to save the lives of so many of our fellow citizens.
Universal Healthcare means everybody is covered and there's many different way to provide such coverage. Canada's is not even a very common approach.
Without that easy-to-cross border, the political pressure to allow private clinics would be irresistible. The law would change.