There is an implicit assumption, perhaps borne out of the relatively 'youth' of the information sector that the only criteria for a successful idea is that it's "good". There are plenty of examples of inventions, ideas or concepts that seem destined to succeed and yet, in the long run, prove unsustainable or unsuitable to break through to a wider market.
Reader and Alerts would appear to be classic examples. Highly marginal services (srsly), filling a specialised but unloved niche (sry), for a set of low value customers (orly). And before anyone starts that up again, talk of "alienating the influencers" is highly exaggerated. Google's influencers are low-fi, not the tech-l33t, as much as it might pain HN.