This is speculation, but I wonder if this is not the outcome of legal compliance efforts with respect to defined data retention periods in various pieces of consumer privacy legislation over the last few years.

From Recital 39 of the GDPR:

"This requires, in particular, ensuring that the period for which the personal data are stored is limited to a strict minimum. Personal data should be processed only if the purpose of the processing could not reasonably be fulfilled by other means. In order to ensure that the personal data are not kept longer than necessary, time limits should be established by the controller for erasure or for a periodic review."

In the context of F500, I've seen compliance efforts around this that have mandated deletion in the case of inactivity for consumer applications that most people would have reasonably assumed would have been kept around even if they didn't log in.

This is hinted at in the article "...to better align with common practices across the industry, the company said on Wednesday." And if we're going to take a cynical view, wouldn't it be that Google would never delete user data (the source of their revenue) unless they absolutely had to?