Sameer wrote about the widespread shift from personal sites and blogs to newsletters and the corresponding shift from RSS to email:
"it's immensely easier for people to put together a newsletter than it is to start a personal site–and especially a lot easier to make money selling newsletter subscriptions. It's also a lot easier to make sure people are reading your stuff through a newsletter, because it arrives in their email inbox"
It doesn't have to be one or the other, it's not a zero sum game, and the same content can be viewed multiple ways giving the reader a choice of how they wish to consume it.
I agree that subscribing to blogs isn't as easy as it should be but it's also not that hard – the main issue is re-educating people in the ways and joys of RSS, especially in our social world, even if it's using a method that doesn't mention they are using RSS.
As I've always said, the muse-letter is intended as a conversation starter. For me, sending out an email letter is not about making sure people are reading it but being a conversation starter, making it easy for people to respond, should they wish, without having to do so in public or worry about where or how they're going to do so – email is familiar and convenient.