Why does an organization in the 21st century need to effectively manage change?

Answer 1

Think about how business was run about 30 years ago. There was no Internet, there were no cell phone (at least not many). Most companies didn't have computers - and certainly not on every desk as we do now.
China and India were not manufacturing competitors - everyone was worried about cheap Japanese labor.

Business is much faster today and it's changing rapidly. Companies must adapt to the change or fall by the wayside.

When was the last time you passed a Lowes or Home Depot and went to the corner hardware store instead?

Answer 2

Change always needs to be managed as much as possible because people resist change (regardless of whether the change is good or bad) so change tends to have a chaotic effect whenever implemented.