Both Google and developers are at fault here. If even Google can't keep an API alive for more than a couple of years, I think it goes without saying you should NEVER rely on ANY API, simply because you should never rely on any other company to dictate your business success or failure. You can test with APIs, play with data, use them as a form of redundancy or simplification of a longer process, but if you're build a sandcastle with other people's sand, you have no one to blame but yourself. You're building a bullshit company.
On the other hand, Google has clearly gone the way of flighty Yahoo, coming out with promising tools then letting them die on the vine. This is not OK - they are wasting developers' time, consumers' time and their own staffs' time. So you can't argue that Google isn't at fault here.