It takes me almost equal time to manage a Kubernetes cluster with 10 nodes as with 100 nodes. If I have to spend say 5 hours per month and with a cost of say 100 usd/hour it means it cost 500 usd/month to manage. If leaving cloud saves say 100 usd/node from 200 usd/node it means for a small company its cost would be (10100)+500=1500 usd/month which is a cost reduction of 25%. For a large company it would be greater (100100)+500=10500 which means a 47.5% savings. Do you see why the savings are greater with scale?