That's entirely the point. A "true platform" is, to Twitter, one where developers come up with new ideas that aren't obvious (hence, your mind being blank trying to come up with one on the spot), then Twitter copies / acquires them and extracts all of the value. It's the exact same thing that Facebook does on its platform (see Dalton Caldwell's experience at Facebook recently), and what OS vendors have done for decades.
I used to have a lot of ideas for Twitter apps, but now I am just confused. Not sure what is allowed and what isn't, and in any case, as you mention, whatever you would build would only have a very limited lifetime anyway. So it is not even fun to think about new ideas for Twitter anymore.
