So three things: 1. talk to your friends about it, I've been advocating it to a lot of people and lots of them are interested. Feedly is relatively easy to setup for a layperson and showing them cool lesser-known feeds is a great way of getting them started (as you all know, there are niche blogs lots of places and the act of self-curation is really empowering). But if you self host, maybe offer to give them an acct...
2. I think gReader was a start but it was a slightly different newsfeed environment. Now everyone I talk to understands the dangers of newsfeeds and algorithmic manipulation, but they don't know what to do. I think there's a space for a RSS startup (or even feedly) to really press their advantage on self-curated feeds and no infinite scrolling that would appeal to a lot of people. The little RSS advertising I see are not focused on this
3. One thing people might miss is some twitter/fb/etc accounts which they know they like, and want to bring to their readers. I think a lot of people know the difference between the people they follow who they actually care about and the ones that are just on the same platforms. I'm thinking especially about Cory Doctorow's Adversarial Interoperability (https://www.ycombinator.com/library/6c-cory-doctorow-on-adve...) but if the platforms won't do it, having a free/open source twitter/fb/etc scraper that is reliable would be a huge win. I've tried some but a lot of them are buggy or expensive and it's annoying for a layperson. This could definitely be improved and I wish some of the platforms would export rss feeds too (e.g. youtube did and then it got weird). Also having easy integration to html-diff non-RSS websites would be great. I've used it to check for job postings, cdc news, etc, and I think a lot of people would like it.
All of which is to say, we have this old technology that is secretly adopted by a lot of websites (especially because of wordpress/etc which make it a default) and which could solve a lot of deep problems that a lot of people are struggling with. I think HN type people could really make impact here in expanding the userbase