For users, it was more of a debacle, with Amazon being one of the biggest companies to rely on stable permissive licensing. Users who could not afford commercial licenses or were unable to accept the new license for legal reasons found themselves in limbo. I am sure that Elastic lost (potential) business to OpenSearch (and AWS). By how much is hard to measure. Sure, they were able to retain enough business. It probably attests to good service and product.
And AWS has agreements with services with similar services, eg MongoDB. Maybe elasticsearch asked for too much money, or AWS didn't want to pay out of principle.