Sadly, I don't think there's any kind of "social contract" with web services providing APIs. Just as the exploitation of crowdsourced data is now common practice (including personal data), most organizations provide APIs only as long as they find free access in their own interest. There's little loyalty or feeling that they owe users anything, at all.
In my most cynical moments, I think the business plan is to provide an API, let it boost your services usage via 3rd party labor, get successful, then buy what you want and lockout the rest.
