For one, not enough people seem to be aware of it. They don't seem to have given that announcement the importance and effort it deserved. Secondly, I can't say that they have a good migration plan when shutting down their services. People scrambling like this to backup the data is rather common these days. And finally, this isn't a service that can be so easily replaced. Even if people knew that it was going away, there would be short-links that they don't remember, but are important nevertheless. Somebody gave an example above - citations in research papers. There isn't much thought given to the consequences when decisions like this are taken.

Granted that it was a free service and Google is under no obligation to keep it going. But if they were going to be so casual about it, they shouldn't have offered it in the first place. Or perhaps, people should take that lesson instead and spare themselves the pain.