Saying “it’s expensive to maintain” and killing it because it competed with, and was better than Google+ without giving them control, was such BS. That so many smart people built and run clones as one man shows proves that Google could have maintained it for next to nothing.
I hope they never kill Google scholar.
So in the context of the times (I joined Google roughly around when this all went down, but this is not insider information, I'm just speculating) I can imagine how it happened -- it likely became hard to staff the project. It probably became hard to "demonstrate impact" by doing incremental changes on it, and little desire on the company's part to put a major push on launching new features or migrating it to new tech stack etc. etc. People working on it could have transferred to any number of higher impact projects and done better for themselves in the corporate career success game.
No manager would have the "power" to demand that the people involved stay working on the project.
So if it needed technical work, and no product managers saw a future for it, and few if any engineers wanted to work on it, and Google was in the middle of pushing its energies behind G+... It seems inevitable for a project like that to die. It was likely dying internally long before it was killed externally. That's my educated guess anyways.
The costs of storage and bandwidth of something as popular as Google Reader probably weren't negligible.
The newsblur dev is in this thread and he runs a good reader and could probably say what the storage and bandwidth was.
Although the 80/20 rule is in effect, and when I query the DB I find that 80% of feeds have only a single active subscriber and 20% of feeds have 2+ active subscribers (activity in the past 30 days). But that's still quite a bit one-to-many fetching savings. And the majority of fetches are 304s.