No, that's what Urban Airship decided to do with the service they bought. We're dealing with the only continuing entity in the equation here, Urban Airship, which is not going out of business. Urban Airship is making the decision to abandon their customers (they bought them) in a crappy manner.

Without working at Urban Airship or SimpleGeo (or being close to someone who does), how would one know that when Urban Airship said they were excited to acquire SimpleGeo to continue improving the service that it was BS, and that the search for a replacement should have been started?

More to the point, a more trustworthy company would comport in such a way that its paying customers don't need to know the difference. In this case, that might mean open sourcing components or giving enough notice that their customers could reasonably transition. A link to the R-Tree wikipedia page is not what I'd expect from a reliable vendor.