This is why distributed systems is an extremely important discipline.
Hell, maybe making today's tech workplace more about getting work done instead of the series of ritualistic performances that the average tech workday has degenerated to might help too.
Ergo, your conclusion doesn't follow from your initial statements, because interviews and workplaces are both far more broken than most people, even people in the tech industry, would think.
Many companies on Vercel don't think to have a strategy to be resilient to these outages.
I rarely see Google, Ably and others serious about distributed systems being down.
But that's the job of Vercel and it looks like they did a pretty good job. They rerouted away from the broken region.
Serious engineering teams that care about distributed systems and multi region deployments don't think like this.