Because they cite not enough users as the main reason for deprecating it? Oh, wait, somehow they don't mention that at all...

Maybe or maybe not. We don't know what the exact numbers were and what they needed to be to keep them in tact. They may have deprecated them anyway to keep a single SDK (at least that's kind of the impression I got though if the usage was high the timeline would probably be longer and more features would be in the core SDK).

It's easy to lambast someone because someone didn't want to rely on another's API but it's a very good point to bring up. Big companies such as Google regularly kill things people use and start-ups are encouraged to think fast, test fast; I have a hard time wanting to rely on either for my business.

Developers that build products on top of APIs controlled by other companies, particularly recent startups, are routinely abused. The upside of these products is unnaturally clipped due to moral hazard on the part of the API provider. That is, closed APIs incentivize their providers to farm out testing new products based on their data set to others, then reimplement the most successful products themselves, and finally cut off access to the developer because it's now a 'competitor'. This pattern has (allegedly) played out with several of the big closed API providers.

This behavior has a double benefit to the API provider, because it potentially turns would be direct competitors who would otherwise work on an alternative to its core technology if not provided with an API into unpaid new product idea validators that leave the API provider the option of crippling their product at will. That's a lot of competitive advantage, especially in markets dominated by network and first mover effects.

As a developer, it's prudent to be skeptical of closed API providers, because developer time is valuable, and the incentives of API providers and consumers are not aligned.

An API has to be extremely valuable in order to overcome these structural issues, and it appears that developers didn't regard these APIs as sufficiently valuable. So in my mind, the blame for this failure doesn't lie with the developers that failed to use the APIs, but with the company that didn't provide a sufficiently attractive API.

We don't know the right scale of desired adoption. For some companies 10k users is a lot but for others like Google, even with tenth of millions [1] they shutdown services like Google Reader.

[1] http://www.lifehacker.com.au/2013/03/how-many-users-does-goo...

Number of users using an API does not determine if it's deprecated or not. If they are making more money (directly or indirectly) than they are spending to run/maintain the API is what determines it most times. There are countless examples of heavily used API's being pulled, Twitter and Netflix spring to mind...