Google search thrived from the third party websites. RSS incentivized and enabled those third-party websites. By killing the reader and RSS, they helped consolidate the web into unsearchable walled gardens like Facebook. If those decision makers still work in Google, that's a reason for continuing Google's downfall.
The decision was probably based on two reasons:
1. They wanted users to discover content using their algorithm as opposed to manual subscriptions to RSS thus depriving users of content Discovery agency.
The decision was probably based on two reasons:
1. They wanted users to discover content using their algorithm as opposed to manual subscriptions to RSS thus depriving users of content Discovery agency.
2. They wanted to promote Google