On August 14, 2003, the Northeast Blackout struck the northeastern US and Canada, leaving 50 million people without power. Many companies depending solely on their own datacenters stopped operations—but financial institutions with geographically distant DR sites survived. This event embedded "DR is not IT's insurance but the core of Business Continuity" across the industry. Twenty years later, AWS commoditized DR by replacing what would cost hundreds of millions in on-premises building a second datacenter with a few API calls.
In SAP-C02 exams, understanding DR as "turning on backups" stays at SAA level