I've done so at two companies (without naming names). Not entirely, but enough to have a bargaining chip with AWS. At the largest company, our monthly bill was at least $1M at AWS, so the savings more than made up for the engineering time.

Also, in both cases, it was moving from AWS to GCP, and in both cases we were using Kubernetes and not really using much of the provided services of the platforms. I suspect this is the biggest reason for Google to push Kubernetes; abstract away compute so it's easier to switch.