As an Android and iOS developer, it is tough to support all possible screen sizes, aspect ratios, hardware specs and versions of Android. Sometimes not having a newer version of Android(>= 4.0) you miss a lot of features that people come to expect and your code is riddle with backwards compatibility stuff just to support Gingerbread, or worse(ie: Donut).
And none of this would be a problem if PBS would simply publish the specification for whatever JSON/XML/etc back end they are using to transmit information to the clients about shows and episodes, and use standard RFC-compatible video formats and streaming protocols with no DRM or other nonsense.
Why would it not be a problem? Because the next day the app stores would be full of "SparkleVideoPlayer now supports PBS!" updates for all of the existing streaming video apps and their loyal users. Or if my screen size, aspect ratio, blah, blah, blah is not supported, I can write my own app!
I can understand why the commercial TV outfits want to control everything - they think it's the only way to poison the experience with ads. But why are public broadcasters like PBS, BBC, and Australia's ABC doling the same thing? It's idiotic - the solution to "how do I support a million devices" is simple: "publish the spec so that the taxpaying public can write their own apps".