Honestly, would we still hold this view if we hadn't already invested so much attention in the idea that a visa is an absolute condition?
Obtaining a visa allows travel, but it doesn't always determine the final dates; it's not a guarantee against all risks.
One can spend weeks on a visa application and, if an epidemic breaks out or a surprise strike paralyzes transportation, the trip is canceled, visa or not.
We need to look at this with fresh eyes: the visa is an administrative step, not a shield against all the world's uncertainties.