Could a 'Leave the World Behind' style cyberattack cause chaos in real life?

• In Netflix's "Leave the World Behind," an unknown entity shuts down communications across the US.
• The cyberattack is later explained as part of a "cost-effective way to destabilize a country."
• A cyberwarfare expert told BI an attack like this would require an immense amount of coordination.

Warning: spoilers ahead…

What would the most cost-effective military campaign to destabilize a country look like?

According to Netflix's "Leave the World Behind," which is based on Rumaan Alam's novel of the same name and executive produced by the Obamas, that program begins with "isolation."