The more I think about it, the more reasons there are for the way apps have developed in the last couple years. The focus is certainly another factor. The fact that the people building these apps are often unfunded startups with passion attempting to build a MVP or actually build something period also leads to more focused apps. No kid with a computer can take on a feature set like iTunes - but he can build a clean and functional music player that simply plays music. Another reason is that these apps may become successful is that the kids building them are closer to the consumer. Theres no corporate bureaucracy to cut through. The problems are real things that the developer themselves have often experienced personally. Looking at Snapchat and the CEO's recent frat house, party animal, college days + misogynistic comments, Snapchat was a much of a solution to a problem he was having as it was an app for the world.
Being in Computer Science, I've learned that's the de-facto method of creating a good app, for practice or otherwise -- build something you want to use to solve a problem/make things easier. There's a certain honesty to that simplicity that comes with the app, as you touched upon, and I do like that.