While RSS readers are making a bit of a comeback in certain quarters there's no doubt that, as Sameer puts it, "subscribing to feeds definitely has fallen out of parlance."
RSS is more than a decade old now, but explaining it to mere mortals still hasn’t really been solved. Podcasts apps are also using RSS technology in the background, but they usually have a directory of podcasts which gives you an easy way of subscribing in the app. This solves a lot of problems for average users.
Out in the open web, you have a feed URL and you need to know where to paste it. It's a big UX problem, but I'm not sure it is even solvable. We can build walled gardens or create a directory of blogs with a built-in RSS reader, but in theory, they still lock you into a service.
As a blog author, I still have to figure out the technical aspects of the IndieWeb and as a blog reader, you also have an obligation to find out how to follow blog over RSS. In this process, you can find a balance to lock yourself into a walled garden or choose something else which you can control, but give up some convince along the way.