The trouble with that is that Reader is the Twitter of RSS readers. Why do I say that? Look at iPhone feed readers. Pretty much all of them use your Google Reader account to synchronize unread/read etc. so you don't have to read just on your phone. It's the API and data store for synchronized feed reading.
How many devices do you need to read your RSS feed on anyway? For me it's only my desktop machines and occasionally my phone. That's a pretty low barrier to entry for a new feed reader.
I'm not buying the huge ecosystem argument at all. The problem with the direction Google is taking—not to mention Twitter—is that there is a huge fad fun factor at work here. It's fun to play around with this stuff, but how much useful information can you get out of it? Sure, Twitter is some people's bread and butter (pro bloggers...), RSS is much more powerful for domain experts, for some people all they can really make use of is email.
Personally I think Google Buzz is too late to cash in on the Twitter fad. It's solving Google's business problem, not users'. It'll probably settle into its niche like the rest of Google's stuff, but they'll have to fix this heavy-handed integration stuff.
