Imho, The biggest threat to the public use of RSS is not the shutting down of aggregators, but the dire situation of Feedburner. Since RSS is no longer part of Google's business strategy, it might not be long before Feedburner is sacrificed as part of their annual culling. It's easy to import an OPML file into your new aggregator -- but due to the decouple nature of publishing and subscribing using RSS, if/when Feedburner goes off, millions of content pubilshers will be left in the dark with no way to connect with their subscribers. That's truly worrisome.

I'd elaborated on this in a blog post I wrote a while ago (When Google Reader shut down) -- http://dickfeynman.github.io/blog/writings/what-the-fate-of-...