Does the 3-2-1 backup rule still work today?

For roughly two decades, the standard in data protection has been the 3-2-1 rule. However, this strategy was created before the rise of cloud and SaaS, and the evolution of ransomware has only complicated matters further.
So how applicable is the 3-2-1 method today?
Read on to learn how 3-2-1 has stood up to the test of time and whether it should be changed or abandoned as data protection needs evolve.