I remember the same thing as you, so I think that's correct. But I would say Feedly probably only recouped some single digit percentage of Google readers users. But then there were however many other users who had their relationship with RSS forever fractured from the shutdown of Google reader, and the absence of a smooth off-ramp certainly contributed.
I also think that having the credibility of Google behind RSS contributed to people being comfortable with them, not unlike iPods helping lead to the adoption of podcasts. I shudder to think whether podcasts would even have gotten off the ground without people being socialized into accepting them through the connection to an Apple product. And while I'm not an Apple fan I'm forever grateful for the long term impact on how we consume content.
So I would say the long and short of it is that Feedly helped, but I suspect it was perhaps an order of magnitude smaller in terms of its role as a positive force for RSS than Google.