Well, kind of. They were already working on the official app. Buying AlienBlue was simply a way to force a migration. AlienBlue actually had very little impact on the official app’s functionality, because they weren’t interested in AlienBlue’s code at all; The buyout was for the user base, not the app itself.
This most recent API change is simply the next step in the process. They realized they couldn’t buy out every single third party app, so they just cut off access instead.