> doomsday scenario where Google itself leaks all of this data, which would be unprecedented and is unlikely ... (emphasis added)

From the linked article [1]:

> December 2018: Google+ Bug Exposes 52.5 Million Users’ Data Google+ faced its second big breach of 2018 when a November update created an API bug that exposed data from 52.5 million Google+ accounts. Google fixed the bug within six days, and moved up Google+’s burial date from August to April 2019.

> Google originally decided to terminate Google+ after another breach became public earlier in 2018

and an earlier Google+ bug that was reported in WSJ [2]

> Google Exposed User Data, Feared Repercussions of Disclosing to Public

> Google opted not to disclose to users its discovery of a bug that gave outside developers access to private data. It found no evidence of misuse.

[1]: https://firewalltimes.com/google-data-breach-timeline

[2]: https://www.wsj.com/articles/google-exposed-user-data-feared... (Oct, 2018)