This doesn't really add up given Bezos purchased it in October 2013.
> It also probably did not inspire very much good will from management/ownership when the company's employees started regularly leaking proceedings at company meetings and reporters started making a practice of using social media to criticize management during work hours.
Your thinking is completely backwards. This isn't the first case of a wealthy individual buying journalism in order to destroy it. Why do you think employee backlash happened in the first place?
4 years after the Bezos acquisition?
Elementary reading skills suggest this means they lived in DC for some significant period of time prior to 2017 as a WP reader, moved away from DC for some unknown period living elsewhere as a non-WP reader, moving back to DC in 2017 when they started reading WP again.
They noticed a decline in quality from before and after the acquisition and are using that to conclude that the acquisition didn't impact the quality of the paper. Again, that certainly seems like a strange way to make the point that the purchase didn't impact its quality.