It’s not as if there’s some other mysterious force that maintains Twitter’s API platform, and now poor ol’ Twitter is forced to shut down old technology because there’s simply no other recourse. No.
Twitter, in fact, is the one responsible for its User Streams and Site Streams APIs – the APIs that serve the core functions of these now deprecated third-party Twitter clients. Twitter is the reason these APIs have been stuck in a beta state for nearly a decade. Twitter is the one that decided not to invest in supporting those legacy APIs, or shift them over to its new API platform.
Ugh, Twitter. They don’t like their users. They don’t like the developers that helped make the platform successful. I don’t think they really like themselves. If there is a bad decision that can be made, Twitter will find a way to do it—they’ve proven that over and over again.