The lesson is not "do not build on someone else's platform", but "be careful whose platform you build on". There have been signs for quite some time now that twitter was not particularly supportive of things built on them.
Is there any way to know if one party is more reliable than other? Four years back, was there any way to know that Twitter would limit their APIs and change their terms and conditions the way they have done? If not, isn't the lesson here "do not build on someone else's platform"?
Four years ago, Twitter was headed in a very different direction (and was under different leadership, too). So I'm not sure that it would have been correct to predict that Twitter, as of four years ago, would end up as it is today, since much of that is due to things that happened in the interim.
That said, the writing has been on the wall for quite some time, even if not quite four years.
I remember thinking that something like this was inevitable last year (circa July 2011), and I wasn't even a developer on Twitter's platform, so there were probably signs much earlier than that too.
