Pretty sure I was using TB to read RSS back in 2006 or something like that...
Like you, I was consuming RSS through Thunderbird around that time as well and thought it was really good. I have since moved to something else(many times) as my needs have changed.
In the spirit of HN, the poster maybe wanted a discussion of how the use of RSS has declined and walled gardens took its place which is not good for the longevity and usefulness of knowledge.