You really don’t need to be omnipotent to know it. For months, Canada was hovering at an Rt just above 1.0. Very little more would have been required to tip the balance.
Canada would also have to be okay with completely closed borders for the rest of its existence. Either that or come up with some way to unilaterally enforce COVID countermeasures in every country on Earth simultaneously until it is completely eradicated. I'm sure it was a nice thought when infection rates were low enough, but after thinking long-term about the problem it becomes clear that government mandates can only do much for so long.