I wrote about this recently[1]. The "problem" with RSS, that essentially lead to it falling out of favour, is that it is pure consumption, not interaction. You can't "like" an update that comes to you via RSS, nor comment, nor easily share. It's difficult for sites to monetise it, or track, or promote their own agenda. It's not "social" and since every other site these days needs to be social, whether through aforeme…
This will probably never happen but I maintain the view that if you want the web to become a better place you have to find ways to educate the (average) user.