I think the real reason why Twitter crushes RSS is that RSS is an open standard that is hard to monetize. Twitter is increasingly a closed ecosystem that only Twitter can make money on, which give Twitter plenty of motivation to throw it's resources into a closed network and not an open standard.
Who says RSS is fading? Are twitter posts of years ago accessible via a simple link as are links obtained via RSS? These are honest questions and not snark.
i don't use rss to follow people, i use it to follow output from particular publications and blogs i'm interested in. i don't think i'd gain any usefulness by displaying an avatar pic, i'm just trying to stay up to date on the happenings in the various affinity networks i'm part of or peripherally interested in.