>if a site doesn’t use RSS, Google will fall back to its existing content index to keep users updated.

This sounds like an "embrace extend extinguish" strategy. Piggyback on websites that have RSS for basic functionality, but use Google's control over the browser to ultimately push websites into something like update aggregation to "reduce server load" that allows Google to track people even when they think they are using an open alternative. It's similar to Google's recent move on FlOC. Making small easily reversible moves towards an open web that protect Google's core position from regulation and users choosing alternatives.

EDIT: If Google deserved the benefit of the doubt they wouldn't still be reading people's email to build creepy profiles on everyone's interests and browsing history. I'm not a fool, I'll consider giving them the benefit of the doubt after they stop that and delete all the data they have collected.