However, it has not been a viable platform (one that people actually used) for many years, so while I am saddened that it is finally being shut down, I'm not surprised. Many thanks to Dalton and everyone who built it and kept it going these many years!
http://thenextweb.com/twitter/2013/01/14/twitter-in-2012/
I think what everyone was worried about back then was that Twitter was changing the nature of what Twitter was. Twitter started placing limits on API tokens, introduced new UI in the form of cards, which could also be used for ads, etc. There was a sense that the freedom and openness of the Twitter platform was quickly diminishing.
Twitter's response was basically no response, but in a good way. They slowed down making those sorts of radical changes, and to this day you can still browse Twitter with a 3rd-party app like TweetBot and never see cards or ads.
TweetBot is older than the API cap, so did they roll that back? It was 100,000 users (or 2x current users if that was >100,000 which TweetBot probably was). So if they didn't roll it back I guess TweetBot would have stopped adding clients.